sendmail question

[Vu Pham]

I have two mail servers using sendmail serving domain, say example.com. 
Users on these two servers are identical. I would like to set them up so 
that any emails coming to server1.example.com will be delivered to the 
local users on server1 *and* also delivered to server2.example.com.

I have tried "@example.com    %1 at server2.example.com" in 
/etc/mail/virtusertable in server1, but it ends up all emails are 
delivered only to server2.

One solution is having in /etc/mail/aliases ( or /etc/aliases ) every 
user listed as

user1:	user1, user1 at server2.example.com

but it is not practical for servers with many users, and the 
administrator has to update aliases whenever some users are added to the 
system.

Am looking at README.cf of sendmail but not yet finding out the 
solution. Any advice, please ?


Thanks,

Vu