{"id":21470,"date":"2025-04-09T00:00:00","date_gmt":"2025-04-09T00:00:00","guid":{"rendered":"https:\/\/www.mailgun.com\/blog\/smtp-befehle\/"},"modified":"2026-09-16T02:52:54","modified_gmt":"2026-09-16T02:52:54","slug":"smtp-befehle","status":"publish","type":"blog","link":"https:\/\/www.mailgun.com\/de\/blog\/deliverability\/smtp-befehle\/","title":{"rendered":"Was sind SMTP-Befehle und was m\u00fcssen Sie dar\u00fcber wissen?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Why do we need SMTP commands and what do they do? Well, we use SMTP (Simple Mail Transfer Protocol) commands to communicate with email servers. These commands are essential for initiating and managing the process of sending emails. By issuing commands like &#8222;EHLO&#8220; (which initiates the connection), &#8222;MAIL FROM&#8220; (specifying the sender&#8217;s email address), and others, we can instruct email servers on how to handle the emails we want to send. Without these commands, the email server wouldn\u2019t know how to process and deliver our messages.<\/p>\n\r\n    <nav data-content-type=\"longform\" class=\"toc-block longform-spacings px-5 py-6 px-md-6 px-lg-7 py-md-7 bg-light fs-sm rounded-lg\" aria-labelledby=\"toc-title-1815\"><p class=\"h5 m-0\" id=\"toc-title-1815\">Inhaltsverzeichnis<\/p><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">01<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#what-is-smtp\">What is SMTP?<\/a><\/div><\/div><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">02<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#what-is-esmtp\">What is ESMTP?<\/a><\/div><\/div><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">03<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#what-is-an-smtp-command\">What is an SMTP Command?<\/a><\/div><\/div><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">04<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#do-i-even-need-to-know-smtp-commands\">Do I even need to know SMTP commands?<\/a><\/div><\/div><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">05<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#how-should-an-smtp-session-flow\">How should an SMTP session flow?<\/a><\/div><\/div><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">06<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#what-are-some-essential-smtp-commands\">What are some essential SMTP commands?<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_1-the-helo-or-ehlo-command\">1. The HELO or EHLO command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_2-the-auth-command\">2. The AUTH command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_3-the-mail-from-command\">3. The MAIL FROM command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_4-the-rcpt-to-command\">4. The RCPT TO command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_5-the-data-command\">5. The DATA command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_6-the-bdat-command\">6. The BDAT command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_7-the-vrfy-command\">7. The VRFY command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_8-the-rset-command\">8. The RSET command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_9-the-quit-command\">9. The QUIT command<\/a><a class=\"scrollme link-body-color\" href=\"#anchor_10-the-help-command\">10. The HELP command<\/a><\/div><\/div><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">07<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#what-are-the-smtp-response-codes\">What are the SMTP response codes?<\/a><\/div><\/div><div class=\"d-flex mt-3\"><div class=\"w-auto fw-bold text-accent d-flex me-2\">08<\/div><div class=\"d-flex flex-column\"><a class=\"fw-bold scrollme link-body-color text-accent\" href=\"#wrapping-up\">Wrapping up<\/a><\/div><\/div><\/nav>\n<h2 class=\"wp-block-heading\">What is SMTP?<\/h2>\n\n<p class=\"wp-block-paragraph\">Before an email even hits the inbox, there&#8217;s a lot happening behind the scenes. It starts with <b>TLS<\/b> (Transport Layer Security), which kicks in to encrypt the connection and keep your data safe from prying eyes. Then the <b>SMTP protocol <\/b>takes the wheel, laying out the rules for how that message gets delivered. Every message also carries a <b>header<\/b>\u2014basically the who, what, and when of your email. Want to see the process in action? Fire up your <b>command line<\/b>. With just a few SMTP commands, you can walk through the entire journey from sender to server and spot deliverability issues before they ever become a problem.<\/p>\n\n<p class=\"wp-block-paragraph\">So, what is SMTP? Simple Mail Transfer Protocol (<a href=\"https:\/\/www.mailgun.com\/de\/funktionen\/smtp-server\/\" target=\"_tabs\" rel=\"noopener noreferrer\">SMTP<\/a>) is just a set of rules that handles email sending, receiving, and relaying.<\/p>\n\n<p class=\"wp-block-paragraph\">Here\u2019s a breakdown: <\/p>\n\n<ol class=\"wp-block-list\">\n<li>The SMTP method establishes a connection between your (the sender\u2019s) email client and your SMTP server.<\/li>\n\n\n\n<li>The SMTP server performs a series of verifications.<\/li>\n\n\n\n<li>The SMTP server relies on SMTP to ferry your email to your recipient\u2019s inbox provider, like Microsoft Outlook or Gmail.<\/li>\n\n\n\n<li>Then SMTP severs the connection between your email client and the SMTP server.<\/li>\n<\/ol>\n\n<p class=\"wp-block-paragraph\">To complete the email sending-and-receiving process, your recipient\u2019s email client uses IMAP (another protocol) to download messages from the receiving IMAP email server when your subscriber decides to check their email. IMAP helps manage emails so your recipients can interact with them in their mailbox UI.<\/p>\n    <div data-content-type=\"longform\"  class=\"callout text-body-color px-5 py-6 px-md-6 px-lg-7 py-md-7 longform-spacings rounded-lg bg-light\" data-theme=\"light\">\r\n\r\n        <div class=\"content-body\"> Want to know more about SMTP and how it works? If you\u2019re an email geek like us, the answer is yes. Check out our post on <a href=\"https:\/\/www.mailgun.com\/de\/blog\/deliverability\/was-ist-smtp\/\">what is SMTP and how does it work to learn more.<\/a><\/div>\r\n    <\/div>\r\n\n<h2 class=\"wp-block-heading\">What is ESMTP?<\/h2>\n\n<p class=\"wp-block-paragraph\">Hang in there, just one more acronym before we get into commands. ESMTP (Extended Simple Mail Transfer Protocol) extends the capabilities of SMTP to allow sharing of multimedia files, like pictures, audio files, and videos. ESMTP includes additional commands allowing the following functionalities:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>Sender authentication<\/li>\n\n\n\n<li>Encrypting emails with SSL<\/li>\n\n\n\n<li>Attaching multimedia files<\/li>\n\n\n\n<li>Restricting email size based on server specifications<\/li>\n\n\n\n<li>Simultaneous transmission to several recipients<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">Below, we\u2019ll go over both ESMTP and SMTP commands.<\/p>\n\n<h2 class=\"wp-block-heading\">What is an SMTP Command? <\/h2>\n\n<p class=\"wp-block-paragraph\">An <b>SMTP command<\/b> is a specific instruction sent from an email client to a mail server that tells it what action to perform\u2014like sending a message, specifying a sender or recipient, or starting a secure connection.<\/p>\n\n<h2 class=\"wp-block-heading\">Do I even need to know SMTP commands?<\/h2>\n\n<p class=\"wp-block-paragraph\">Yes: If you\u2019re an email developer, you need to know SMTP commands. But if you\u2019re a regular Gmail account user, you can probably save your brain space for random Game of Thrones trivia.<\/p>\n\n<p class=\"wp-block-paragraph\">SMTP commands are used in a particular sequence to facilitate communication between two servers to deliver an email. Here are a few scenarios in which you might want to know SMTP commands:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>You want to configure SMTP on your computer or network<\/li>\n\n\n\n<li>You need to troubleshoot your email service<\/li>\n\n\n\n<li>You need to contact your SMTP server<\/li>\n\n\n\n<li>Okay, this one\u2019s pretty specific, but what if you want to access email in the middle of a Telnet session? Telnet allows you to virtually access a computer and implement remote, collaborative two-way access<\/li>\n\n\n\n<li>Also specific: you\u2019re trying to send emails from inside a Linux shell<\/li>\n\n\n\n<li>You want to run an SMTP test<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">If any of these use cases sound familiar, read on!<\/p>\n\n<h2 class=\"wp-block-heading\">How should an SMTP session flow?<\/h2>\n\n<p class=\"wp-block-paragraph\">Think of an SMTP session as a dialogue between your client and an SMTP server. You send out commands with alphabetical characters, and the server responds with numeric codes.<\/p>\n\n<p class=\"wp-block-paragraph\">What\u2019s a client, you ask? Clients can be your email client, like Gmail, which issues commands on your behalf. Or they can be a terminal that you use to issue commands.<\/p>\n\n<p class=\"wp-block-paragraph\">Usually, SMTP sessions follow a standard sequence:<\/p>\n\n<ol class=\"wp-block-list\">\n<li><b>Handshake: <\/b>The client and the server establish a Transmission Control Protocol (TCP) connection<\/li>\n\n\n\n<li><b>Email transfer: <\/b>The client passes your email message to the SMTP server, and the server performs authentication checks<\/li>\n\n\n\n<li><b>Termination: <\/b>The client and the server close the TCP connection<\/li>\n<\/ol>\n\n<h2 class=\"wp-block-heading\">What are some essential SMTP commands?<\/h2>\n\n<p class=\"wp-block-paragraph\">Now that we know how an SMTP session looks, let\u2019s go over some essential <a href=\"https:\/\/datatracker.ietf.org\/doc\/html\/rfc5321#section-4.1\" target=\"_tabs\" rel=\"noopener noreferrer\">SMTP and ESMTP commands<\/a>. We\u2019ve listed these in the <a href=\"https:\/\/datatracker.ietf.org\/doc\/html\/rfc5321#section-4.3.2\" target=\"_tabs\" rel=\"noopener noreferrer\">sequence in which they might be used<\/a>:<\/p>\n\n<ol class=\"wp-block-list\">\n<li>The <i>HELO <\/i>or <i>ELHO<\/i> command<\/li>\n\n\n\n<li>The <i>AUTH<\/i> command<\/li>\n\n\n\n<li>The <i>MAIL FROM<\/i> command<\/li>\n\n\n\n<li>The <i>RCPT TO<\/i> command<\/li>\n\n\n\n<li>The <i>DATA <\/i>command<\/li>\n\n\n\n<li>The <i>BDAT<\/i> command<\/li>\n\n\n\n<li>The <i>VRFY<\/i> command<\/li>\n\n\n\n<li>The <i>RSET <\/i>command<\/li>\n\n\n\n<li>The <i>QUIT <\/i>command<\/li>\n\n\n\n<li>The <i>HELP <\/i>command<\/li>\n<\/ol>\n\n<h3 class=\"wp-block-heading\">1. The <i>HELO<\/i> or <i>EHLO <\/i>command<\/h3>\n\n<p class=\"wp-block-paragraph\">The first command you\u2019ll need to know is the <i>HELO<\/i> command. <i>HELO<\/i> starts the SMTP session and allows the client to greet the server and introduce itself. The command takes the domain name or IP address of the SMTP client as an argument, as shown below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    HELO mailgun.net\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<p class=\"wp-block-paragraph\">The <i>HELO<\/i> command is <a href=\"https:\/\/datatracker.ietf.org\/doc\/html\/rfc5321#appendix-F.3\" target=\"_tabs\" rel=\"noopener noreferrer\">mostly considered obsolete<\/a>, but SMTP clients and mechanisms are required to support it as a fallback for conversing with older implementations.<\/p>\n\n<p class=\"wp-block-paragraph\">Remember how we said above that ESMTP extended SMTP? As such, ESMTP sometimes has different commands from SMTP. <i>EHLO<\/i> is the ESMTP alternative to SMTP <i>HELO<\/i> for servers that support ESMTP. The SMTP server will respond with an SMTP error code if it doesn\u2019t support ESMTP. In this case, you\u2019ll have to start the handshake process all over again. Check out the sample ESMTP command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    EHLO mailgun.net\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h3 class=\"wp-block-heading\">2. The <i>AUTH<\/i> command<\/h3>\n\n<p class=\"wp-block-paragraph\">The <i>AUTH<\/i> command is an ESMTP command that authenticates the SMTP client to the SMTP server. It can take different keywords, depending on the level of security and the login method: <i>PLAIN<\/i>, <i>LOGIN<\/i>, and <i>CRAM-MD5<\/i>. Your session is authenticated when the server provides a positive response. Check out the <i>AUTH <\/i>command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    AUTH CRAM-MD5\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<p class=\"wp-block-paragraph\">Learn more about <a href=\"https:\/\/www.samlogic.net\/articles\/smtp-commands-reference-auth.htm\" target=\"_tabs\" rel=\"noopener noreferrer\"><i>AUTH <\/i>command keywords<\/a>.<\/p>\n\n<h3 class=\"wp-block-heading\">3. The <i>MAIL FROM <\/i>command<\/h3>\n\n<p class=\"wp-block-paragraph\">After you\u2019ve initiated the client-server handshake with a <i>HELO <\/i>or <i>EHLO<\/i> command, you can use the <i>MAIL FROM <\/i>command to start a mail transfer. Specifically, you (as the sender) state the sender\u2019s email address in the \u201cfrom\u201d field. The <i>MAIL FROM <\/i>command takes the \u201cfrom\u201d email address as an argument, as shown in the SMTP example code below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    MAIL FROM &quot;test@mailgun.net&quot;\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h3 class=\"wp-block-heading\">4. The <i>RCPT TO<\/i> command<\/h3>\n\n<p class=\"wp-block-paragraph\">Use the <i>RCPT TO<\/i> command to specify the recipient as an argument. If you have more than one recipient, use <i>RCPT TO<\/i> to specify each recipient separately. Check out the sample <i>RCPT TO<\/i> command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    RCPT TO &quot;subscriber@recipientsinbox.com&quot;\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h3 class=\"wp-block-heading\">5. The <i>DATA <\/i>command<\/h3>\n\n<p class=\"wp-block-paragraph\">The <i>DATA<\/i> command is how your SMTP client asks the SMTP server for permission to transfer your email message (the data). Once the server has responded with a 354 code to grant permission, the client delivers your email content line-by-line. Use a final line with a period (\u201c.\u201d) to terminate the data transfer.<\/p>\n\n<p class=\"wp-block-paragraph\">Check out the example <i>DATA<\/i> command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    DATA\r\n354 (server response code)\r\nDate: Wed, 30 July 2022 06:04:34\r\nFrom: test@mailgun.net\r\nSubject: SMTP session tutorial\r\nTo: subscriber@recipientsinbox.com\r\nBody text\r\n.\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h3 class=\"wp-block-heading\">6. The <i>BDAT<\/i> command<\/h3>\n\n<p class=\"wp-block-paragraph\">The <i>BDAT<\/i> command is the ESMTP version of the <i>DATA <\/i>command that transfers email content. <i>BDAT<\/i> takes two arguments:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>The length of the data chunk (in octets)<\/li>\n\n\n\n<li>An indicator that the data chunk is terminating<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">Check out the sample <i>BDAT<\/i> command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    BDAT 67 LAST\r\nTo: subscriber@recipientsinbox.com\r\nFrom: test@mailgun.net\r\nSubject: SMTP session tutorial\r\n250 Message OK, 67 octets received\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<p class=\"wp-block-paragraph\"><i>BDAT<\/i> is used in the Microsoft Exchange Server.<\/p>\n\n<h3 class=\"wp-block-heading\">7. The <i>VRFY<\/i> command<\/h3>\n\n<p class=\"wp-block-paragraph\">Issue the <i>VRFY <\/i>command to ask the server to confirm that a particular username or mailbox exists on the localhost. Note that some SMTP email servers ignore the <i>VRFY <\/i>command since it can be a security loophole that hackers exploit to lift email addresses. Take a look at a sample <i>VRFY<\/i> command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    VRFY user2\r\n250 Jada Jonesjadaj@mailgun.net\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h3 class=\"wp-block-heading\">8. The <i>RSET<\/i> command<\/h3>\n\n<p class=\"wp-block-paragraph\">Ready to reset your SMTP connection to the initial state without severing your connection? Use the <i>RSET<\/i> command. This command takes no arguments. Check out the sample command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                HTML                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-markup\">\r\n                                <code id=\"code_0_content\" class=\"language-markup\">\r\n\r\n                                    RSET\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h3 class=\"wp-block-heading\">9. The <i>QUIT<\/i> command<\/h3>\n\n<p class=\"wp-block-paragraph\">Okay, let\u2019s say you\u2019re finished with your SMTP session. You want to clear the data and terminate your session. Simply use the <i>QUIT<\/i> command. Once the server responds with a 221 code, your client will close the connection. Check out the sample <i>QUIT<\/i> command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    QUIT\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h3 class=\"wp-block-heading\">10. The <i>HELP<\/i> command<\/h3>\n\n<p class=\"wp-block-paragraph\">This is probably the most useful command. Need help but don\u2019t know where to turn? Try the <i>HELP<\/i> command first. This command pulls up a list of possible commands that the SMTP server supports. You can supply specific commands as an argument to the <i>HELP<\/i> command to get help with specific commands. Check out the example <i>HELP<\/i> command below.<\/p>\n    <div data-content-type=\"longform\" class=\"code-snippet longform-spacings rounded-lg overflow-hidden shadow \" data-count=\"1\">\r\n        <ul class=\"nav nav-buttons code-snippet__tabs longform-except position-relative d-flex gap-2 flex-wrap p-3\" role=\"tablist\">\r\n\r\n                            \r\n                    \r\n                        <li class=\"nav-item\" role=\"presentation\">\r\n                            <button class=\"nav-link active\" data-bs-toggle=\"tab\" data-bs-target=\"#code_0\" type=\"button\" role=\"tab\" aria-controls=\"code_0\" aria-selected=\"true\">\r\n                                PHP                            <\/button>\r\n                        <\/li>\r\n\r\n                    \r\n                            \r\n        <\/ul>\r\n        <div class=\"code-snippet__tab-content tab-content\">\r\n\r\n                            \r\n                    <div class=\"tab-pane show active\" id=\"code_0\" role=\"tabpanel\" aria-labelledby=\"code_0\">\r\n                        <div class=\"code-snippet__code-wrapper\">\r\n                            <div class=\"nav nav-buttons code-snippet__copy-wrapper\">\r\n                                <button type=\"button\" class=\"nav-link code-snippet__copy\" data-clipboard-target=\"#code_0_content\" data-clipboard-label=\"In die Zwischenablage kopieren\" data-clipboard-success-label=\"Kopiert\" data-clipboard-error-label=\"Kopieren nicht m\u00f6glich\" data-tooltip=\"In die Zwischenablage kopieren\" data-tooltip-placement=\"left\" role=\"tooltip\" aria-label=\"In die Zwischenablage kopieren\">\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--default\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/file-stack.svg\"><\/svg>\r\n                                    <svg class=\"code-snippet__copy-icon code-snippet__copy-icon--success\" width=\"24\" height=\"24\" aria-hidden=\"true\" data-url=\"https:\/\/www.mailgun.com\/wp-content\/plugins\/sinch-core\/assets\/icons\/sinch\/badge-check.svg\"><\/svg>\r\n                                <\/button>\r\n                            <\/div>\r\n                            <pre class=\"w-100 h-100 m-0 line-numbers language-PHP\">\r\n                                <code id=\"code_0_content\" class=\"language-PHP\">\r\n\r\n                                    HELP\r\n                                <\/code>\r\n                            <\/pre>\r\n                        <\/div>\r\n                    <\/div>\r\n                                    <\/div>\r\n    <\/div>\r\n\n<h2 class=\"wp-block-heading\">What are the SMTP response codes?<\/h2>\n\n<p class=\"wp-block-paragraph\">If SMTP commands are how you communicate with an SMTP server via an email client, how does the SMTP server talk to you? That\u2019s easy: through <a href=\"https:\/\/datatracker.ietf.org\/doc\/html\/rfc5321#section-4.2\" target=\"_tabs\" rel=\"noopener noreferrer\">SMTP response codes<\/a>.<\/p>\n\n<p class=\"wp-block-paragraph\">SMTP response codes are three-digit numeric sequences. Each digit tells you something different. Consider a response code of 250:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>The first digit (\u201c2\u201d) <b>indicates if your command was good, bad, or incomplete<\/b><\/li>\n\n\n\n<li>The second digit (\u201c5\u201d) tells you <b>what kind of response<\/b> was sent<\/li>\n\n\n\n<li>The third digit (\u201c0\u201d) <b>gives additional information<\/b> about your command<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">As you can imagine, the first digit is the most important because it gives you an idea about whether or not your command worked. Check out the following table from <a href=\"https:\/\/tools.ietf.org\/html\/rfc5321#section-4.2.1\" target=\"_tabs\" rel=\"noopener noreferrer\">RFC 5321 (Simple Mail Transfer Protocol)<\/a> that lays out what various first digits mean: <\/p>\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\nRepl\u00ady code\u00ad\n<\/th><th>\nMean\u00ading\n<\/th><\/tr><\/thead><tbody><tr><td>\n2.y.z\n<\/td><td>\nThe comm\u00adand that\u00ad was sent\u00ad was succ\u00adessfully comp\u00adleted on the remo\u00adte serv\u00ader. The remo\u00adte serv\u00ader is read\u00ady for the next\u00ad comm\u00adand.\n<\/td><\/tr><tr><td>\n3.y.z\n<\/td><td>\nThe comm\u00adand was acce\u00adpted, but the remo\u00adte serv\u00ader need\u00ads more\u00ad info\u00adrmation befo\u00adre the oper\u00adation can be comp\u00adleted. The send\u00ading serv\u00ader need\u00ads to send\u00ad a new comm\u00adand with\u00ad the need\u00aded info\u00adrmation.\n<\/td><\/tr><tr><td>\n4.y.z\n<\/td><td>\nThe comm\u00adand wasn\u00ad&#8217;t acce\u00adpted by the remo\u00adte serv\u00ader for the reas\u00adon that\u00ad migh\u00adt be temp\u00adorary. The send\u00ading serv\u00ader shou\u00adld try to conn\u00adect agai\u00adn late\u00adr to see if the remo\u00adte serv\u00ader can succ\u00adessfully acce\u00adpt the comm\u00adand. The send\u00ading serv\u00ader will\u00ad cont\u00adinue to retr\u00ady the conn\u00adection unti\u00adl eith\u00ader a succ\u00adessful conn\u00adection is comp\u00adleted (ind\u00adicated by a 2.y.\u00adz code\u00ad) or fail\u00ads perm\u00adanently (ind\u00adicated by a 5.y.\u00adz code\u00ad). An exam\u00adple of a temp\u00adorary SMTP\u00ad erro\u00adr is low stor\u00adage spac\u00ade on the remo\u00adte serv\u00ader. Once\u00ad more\u00ad spac\u00ade is made\u00ad avai\u00adlable, the remo\u00adte serv\u00ader shou\u00adld be able\u00ad to succ\u00adessfully acce\u00adpt the comm\u00adand.\n<\/td><\/tr><tr><td>\n5.y.z\n<\/td><td>\nThe comm\u00adand wasn\u00ad&#8217;t acce\u00adpted by the remo\u00adte serv\u00ader for the reas\u00adon that\u00ad isn&#8217;\u00adt reco\u00adverable. The send\u00ading serv\u00ader won&#8217;\u00adt retr\u00ady the conn\u00adection and will\u00ad send\u00ad a non-\u00addelivery repo\u00adrt back\u00ad to the user\u00ad who sent\u00ad the mess\u00adage. An exam\u00adple of an unre\u00adcoverable erro\u00adr is a mess\u00adage that\u00ad&#8217;s sent\u00ad to an emai\u00adl addr\u00adess that\u00ad does\u00adn&#8217;t exis\u00adt.\n<\/td><\/tr><\/tbody><\/table><\/figure>\n\n<h2 class=\"wp-block-heading\">Wrapping up<\/h2>\n\n<p class=\"wp-block-paragraph\">And that\u2019s it! We know, super light and easy info. Whether you\u2019re looking for an <a href=\"https:\/\/www.mailgun.com\/de\/blog\/product\/getting-started-with-mailgun-introduction-to-platform-training\/\" target=\"_tabs\" rel=\"noopener noreferrer\">SMTP server solution<\/a> to power your email sending, or if you\u2019re looking for details on exactly what <a href=\"https:\/\/www.mailgun.com\/de\/blog\/email\/welchen-smtp-port-verwenden-die-ports-25-465-587-verstehen\/\" target=\"_tabs\" rel=\"noopener noreferrer\">SMTP port<\/a> to use (25? 587? 2525?), Mailgun\u2019s got you covered.<\/p>\n\n<p class=\"wp-block-paragraph\">As always, don\u2019t hesitate to reach out. Let us help you get sending today.<\/p>\n\r\n    <aside data-content-type=\"longform\"  class=\"banner-block longform-spacings rounded-lg shadow-lg px-5 py-6 px-md-6 py-md-7 p-lg-7 bg-light\" data-theme=\"dark\" aria-labelledby=\"banner-block-block_746626819f3a6a39ea214d792937ca1d\">\r\n                    <p class=\"text-uppercase section-caption text-body-color\">\r\n                Learn more about SMTP with Sinch Mailgun            <\/p>\r\n                            <p class=\"h4 text-accent fw-bold\" id=\"banner-block-block_746626819f3a6a39ea214d792937ca1d\">\r\n                SMTP relay service &#8211; try for free            <\/p>\r\n                            <div class=\"mb-0 text-body-color\">\r\n                                    <div class=\"content-body mb-0 text-body-color\">Particularly for growing businesses, you want access to powerful features, real-time analytics, and the ability to scale as both your email marketing and outgoing mail multiplies. That flexibility is at the core of Mailgun so as your business and marketing campaigns evolve, your free SMTP service doesn\u2019t have to change.<\/div>\r\n                            <\/div>\r\n        \r\n        <div class=\"text-start mt-5\"><a href=\"https:\/\/www.mailgun.com\/de\/funktionen\/smtp-server\/\"  class=\"btn btn-secondary\" >SMTP Relay Service &#8211; Try for free<\/a><\/div>\r\n    <\/aside>\r\n\r\n","protected":false},"excerpt":{"rendered":"<p>Dieser Artikel behandelt, was SMTP-Befehle sind und wie Sie mit Ihrem SMTP-Server kommunizieren. Anschlie\u00dfend stellen wir Ihnen einige wichtige SMTP-Befehle und Antwortcodes vor.<\/p>\n","protected":false},"author":13,"featured_media":4376,"menu_order":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"blog_category":[21],"class_list":["post-21470","blog","type-blog","status-publish","has-post-thumbnail","hentry","blog_category-deliverability"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Ihr Leitfaden f\u00fcr SMTP-Befehle und Best Practices - Transactional Email API Service For Developers | Mailgun<\/title>\n<meta name=\"description\" content=\"Sie m\u00f6chten also mit Ihrem SMTP-E-Mail-Server kommunizieren und E-Mails versenden? 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