我目前已设置 postfix 来通过 gmail 中继来自我网站的消息，直到最近它都运行正常。然而，在过去一周左右的时间里（不太确定是什么时候），每当我尝试发送电子邮件时，我都会收到以下错误：
Jul 20 07:40:46 localhost postfix/smtp[11958]: connect to smtp.gmail.com[2001:4860:800a::6c]:587: Network is unreachable
Jul 20 07:40:46 localhost postfix/smtp[11958]: connect to smtp.gmail.com[173.194.76.109]:587: Connection refused
Jul 20 07:40:46 localhost postfix/smtp[11958]: connect to smtp.gmail.com[173.194.76.108]:587: Connection refused
这是我的配置文件：
# 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 $mail_name (Ubuntu)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
#readme_directory = no
# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${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.
myhostname = [my domain name]
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
#myorigin = /etc/mailname
mydestination = [my host name], localhost.localdomain, localhost
relayhost = [smtp.gmail.com]:587
mynetworks = 127.0.0.0/8
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = loopback-only
inet_protocols = all
##########################################
##### non debconf entries start here #####
##### client TLS parameters #####
smtp_tls_loglevel=1
smtp_tls_security_level=encrypt
smtp_sasl_auth_enable=yes
smtp_sasl_password_maps=hash:/etc/postfix/sasl/passwd
smtp_sasl_security_options = noanonymous
##### map username@localhost to [email protected] #####
smtp_generic_maps=hash:/etc/postfix/generic
据我所知，我的服务器上没有任何变化...有什么想法可能导致它停止工作？
答案1
由于这是通过 ipv6 进行的尝试，因此可以忽略网络不可达
您还需要强制使用 tls 来加密连接，这里有一个很好的描述
http://blog.chriskankiewicz.com/post/253/postfix-using-gmail-as-a-relay-host/
答案2
在 DNSBLs 中检查您的 IP 地址。您可能已被列入黑名单，或者这是临时问题。
答案3
我的猜测是通信失败（防火墙问题？）“网络无法访问” - 然后“连接被拒绝”。连接被拒绝也可能是 Gmail 拒绝您的连接，也许您超过了每个帐户的发送限制？