所以我有几台 RHEL 7.3 服务器，无法启动未改动过的 postfix 守护进程。我没有更改任何配置文件，因此服务应该可以正常启动，虽然可能无法正常工作，但至少应该可以启动。
以下是启动失败时 journalctl -xe 的输出
-- Unit postfix.service has begun starting up.
Apr 11 23:36:08 postfix/postfix-script[31187]: starting the Postfix mail system
Apr 11 23:36:08 postfix/master[31189]: fatal: 127.0.0.1:smtp: Servname not supported for ai_socktype
Apr 11 23:36:09 postfix/master[31188]: fatal: daemon initialization failure
Apr 11 23:36:10 postfix/postfix-script[31190]: fatal: mail system startup failed
Apr 11 23:36:10 systemd[1]: postfix.service: control process exited, code=exited status=1
Apr 11 23:36:10 systemd[1]: Failed to start Postfix Mail Transport Agent.
-- Subject: Unit postfix.service has failed
以下是 postconf 信息
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
ddd $daemon_directory/$process_name $process_id & sleep 5
html_directory = no
inet_interfaces = localhost
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.10.1/README_FILES
sample_directory = /usr/share/doc/postfix-2.10.1/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
unknown_local_recipient_reject_code = 550
答案1
检查端口名称是否smtp定义在/etc/services：
grep smtp /etc/services
Postfix 主进程读取/etc/postfix/master.cf配置文件以了解应启动和控制哪些 Postfix 服务。其中之一是smtpd用于接收邮件的服务。配置文件使用符号名称简体中文:指定此服务将监听哪个端口。通常，您的系统应在文件中定义此端口和其他端口名称/etc/services。但您的错误消息127.0.0.1:smtp: Servname not supported for ai_socktype表明 Postfix 无法将名称转换为数字。也许该/etc/services文件不存在，或者 Postfix 无法读取它，或者它不包含 的条目smtp。在这些情况下，Postfix 可能不应该受到指责，您系统上的其他网络应用程序也可能存在问题。