因此我尝试按照本教程在我的 raspberry pi 4 上运行 postfix 应用程序：https://raspberrytips.com/邮件服务器-raspberry-pi/但是当我尝试使用 telnet 向外部邮箱发送电子邮件（例如我的 gmail）时，我永远收不到它。这是我的 main.cf 文件
# 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 $mail_name (Raspbian)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on
# fresh installs.
compatibility_level = 2
# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_d$
myhostname = domain.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, example.xyz, domain.com, localhost.com, localhost
relayhost =
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 = ipv4
myhostname = example.xyz
home_mailbox = Maildir/
mailbox_command =
（所有 Example.xyz 均被替换为指向 Raspberry Pi IP 的域名）
以下是使用 telnet 的响应
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 example.xyz ESMTP Postfix (Raspbian)
ehlo example.xyz
250-example.xyz
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250-SMTPUTF8
250 CHUNKING
mail from: [email protected]
250 2.1.0 Ok
rcpt to: [email protected]
250 2.1.5 Ok
data
354 End data with <CR><LF>.<CR><LF>
Subject: test
Test
.
250 2.0.0 Ok: queued as E8BA9DD6B6
quit
221 2.0.0 Bye
Connection closed by foreign host.
但我从未收到过 Gmail 邮件