如何讓 gmail 使用 postfix 作為 SMTP 伺服器
我正在嘗試讓 gmail 從我的虛域發送電子郵件 - 可以理解，它希望使用為該域設置的 SMTP 伺服器。我嘗試將 postfix 配置為我的虛域的 SMTP 伺服器，但在 gmail 中我不斷收到身份驗證錯誤。我的經驗似乎與Postfix 作為 Gmail 的 SMTP 伺服器非常相似。（“以” google 選項發送郵件） 對於這個特定問題，我在網上幾乎沒有找到其他有用的資訊。大多數其他似乎詢問此問題的使用者都會得到“這是如何將 gmail 用作 SMTP 伺服器”的答案，這顯然沒有幫助。Gmail 無法從我的虛域發送，這就是我（和它）需要 SMTP 伺服器的原因。
這是我的配置文件，我使用 host.example.com 作為執行後綴的伺服器的完整主機和域名。- 我已將 vanity.domain 用作我試圖以不同使用者身份使用 gmail 和 user1 等的虛榮域名。
我添加了 Letsencrypt 證書，因為有人建議 gmail 可能會拒絕自簽名證書。我不知道這是否正確，或者我是否正確地完成了它 - 我在 host.domain.com 上使用了 certbot –apache - 證書在 host.exmaple.com 的瀏覽器中確實有效。
順便說一句，我還沒有設法讓 postfix 使用埠 587 - 所以我從原來的位置刪除了 :587
$$ vanity.domain $$:587 在配置中。 main.cf（由於不同指南建議添加的所有內容，它變得很長）
# See /usr/share/postfix/main.cf.dist for a commented, more complete version # Debian specific: Specifying a file name will cause the first # line of that file to be used as the name. The Debian default # is /etc/mailname. #myorigin = /etc/mailname smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) biff = no # appending .domain is the MUA's job. append_dot_mydomain = no # Uncomment the next line to generate "delayed mail" warnings #delay_warning_time = 4h readme_directory = no # See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on # fresh installs. compatibility_level = 2 # TLS parameters smtpd_tls_cert_file=/etc/letsencrypt/live/host.example.com/fullchain.pem #smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem smtpd_tls_key_file=/etc/letsencrypt/live/host.example.com/privkey.pem #smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key smtpd_use_tls=yes smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache # See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for # information on enabling SSL in the smtp client. smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination myhostname = host.example.com alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases myorigin = /etc/mailname mydestination = $myhostname, host.example.com, host, localhost.localdomain, localhost #relayhost =[vanity.domain]:587 mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 mailbox_size_limit = 0 recipient_delimiter = + inet_interfaces = all inet_protocols = all virtual_alias_domains = vanity.domain virtual_alias_maps = hash:/etc/postfix/virtual smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd smtp_sasl_security_options = noplaintext,noanonymous smtp_sasl_tls_security_options = noanonymous smtp_sasl_auth_enable = yes smtp_use_tls = yes smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt #smtp_tls_security_level = may #smtp_tls_protocols = !SSLv2, !SSLv3 #smtp_tls_mandatory_protocols = !SSLv2, !SSLv3 #smtp_tls_mandatory_ciphers = high smtpd_sasl_type = dovecot smtpd_sasl_path = private/auth smtpd_sasl_local_domain = smtpd_sasl_security_options = noanonymous broken_sasl_auth_clients = yes smtpd_sasl_auth_enable = yes smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination smtp_tls_security_level = may smtpd_tls_security_level = may smtp_tls_note_starttls_offer = yes smtpd_tls_loglevel = 1 smtpd_tls_received_header = yes smtp_tls_security_level = may smtp_tls_protocols = !SSLv2, !SSLv3 smtp_tls_mandatory_protocols = !SSLv2, !SSLv3 smtp_tls_mandatory_ciphers = high smtp_tls_loglevel = 1 sender_canonical_maps = tcp:127.0.0.1:10001 sender_canonical_classes = envelope_sender recipient_canonical_maps = tcp:127.0.0.1:10002 recipient_canonical_classes = envelope_recipient等/後綴/虛擬：
user1@vanity.domain user1@gmail.com user2@vanity.domain user2@gmail.com user3@vanity.domain user3@gmail.com testing@vanity.domain user1@gmail.com @vanity.domain user1@gmail.com我嘗試連接時的日誌（已刪除 ips、日期和時間）：
connect from mail-ua1-f41.google.com Anonymous TLS connection established from mail-ua1-f41.google.com: TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) warning: mail-ua1-f41.google.com: SASL PLAIN authentication failed: lost connection after AUTH from mail-ua1-f41.google.com disconnect from mail-ua1-f41.google.com ehlo=2 starttls=1 auth=0/1 commands=3/4sasl_passwd
[vanity.domain] user1:longpassword最後，在 gmail 的 SMTP 設置中，我填寫以下內容：
smtp 伺服器：host.example.com 使用者：user1（我也試過 user1@vanity.domain 和 user1@host.example.com - 我不確定應該是哪個） 密碼：longpassword 埠：25（試過 587 和 465太）安全性：TLS（嘗試過 SSL 並且不安全）
我放棄了，改用 sendgrid