exim and hostname fqdn problem_exim hostname-优快云博客

本文介绍如何通过配置exim4的DC_minimaldns选项解决启动过程中因网络连接不可用导致的问题，并提供了确保hostname--fqdn命令正确返回全限定域名的方法。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

For some type of setups, if network connections not available during startup process, exim4 takes long time to start. To solve this problem, you must useDC_minimaldns option of exim4. You can also configure this feature with

dpkg-reconfigure exim4-config

on Debian based systems. You should answer Yes for the question "Keep number of DNS-queries minimal?"

However, if hostname --fqdn command doesn't print a full qualified hostname (actually only checked one dot) exim4 gives a warning and DC_minimaldns function doesn't work.

For example your hostname is "debian" and if hostname --fqdn also prints just "debian" this is due to the following behaviour of hostname command:

When used --fqdn parameter, firstly it learns the exact hostname
After hostname is learned, it uses gethostbyname() function and printsh_name field ofhostent structure.

Probably you have a record in /etc/hosts file like that:

127.0.0.1 debian

In this scenario, hostname --fqdn will also just print "debian". To solve this you must write a dotted hostname first in /etc/hosts file like that:

127.0.0.1 debian.localhost debian

After that hostname --fqdn will print "debian.localhost" and this makes exim4 happy.

PS: exim是英国剑桥大学开发的一款在UNIX下运行的邮件传输代理(MTA)