Exim and hostname FQDN Problem

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 use
DC_minimaldnsOption of exim4. you can also configure this feature

Dpkg-reconfigure exim4-config

On Debian based systems. You shoshould answerYesFor the question"Keep number of DNS-queries minimal?"

 

However, ifHostname -- fqdnCommand 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 usesGethostbyname ()Function and prints
  H_nameFieldHostentStructure.

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

127.0.0.1 Debian

In this scenario,Hostname -- fqdnWill 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 thatHostname -- fqdnWill print"Debian. localhost"And this makes exim4 happy.