Sendmail 8.13..
CentOS 5.1
1. Check following line should be there in /etc/mail/sendmail.mc
FEATURE(`virtusertable’, `hash -o /etc/mail/virtusertable.db’)dnl
FEATURE(always_add_domain)dnl
FEATURE(use_cw_file)dnl
2./etc/mail/virtusertable, which will look something like this:
abc@domain1.com abc
xyz@domain2.com xyz
abc@domain2.com abc2
3. makemap hash /etc/mail/virtusertable < /etc/mail/virtusertable
4. Put host alliases in /etc/mail/local-host-names.
domain1.com
domain2.com