By default, Sendmail uses DNS for name resolution, not the /etc/hosts file. The behaviour can be changed using one of the below methods:

1. If you wish to query the hosts file before DNS servers, create a /etc/mail/service.switch file which contains the following line:

   hosts files dns

   If you wish to query ONLY the hosts file, use the following:

   hosts files

   Send Sendmail a HUP signal:

   kill -HUP `head -1 /var/run/sendmail.pid`

   and the changes will take effect.

2. Open (or create if it doesn’t exist the file /etc/mail/mailertable) and add:hostname-thats-not-working.com esmtp:[ip.addr.addr.addr]Then rebuild mailertable running:makemap hash /etc/mail/mailertable < /etc/mail/mailertableThis should take immediate effect – no need to alter the running process.

 

Jobs a gooden!
 

If you then wish to force any deferred mail currently in the queue you can use:sendmail -OTimeout.hoststatus=0m -q -vThis ensures that the cached DNS is ignored, and the new IP address is looked up.

• deferred
• dns
• linux
• sendmail
• timed out