[TriLUG] sendmail jujitsu with virtual hosts

[Scott Lundgren]

hi all,

I'm having to touch sendmail configuration files for the first time  
in a long while, and while I'm at it I want to know if something is  
possible.

The server a.domain.tld has apache 2.2 and sendmail (no idea what  
version) on solaris 9.
The server hosts virtually the websites of other subdomains of  
domain.tld (b.domain.tld, www.c.domain.tld, and www.d.domain.tld).
The subdomains are properly set up in DNS to be aliased to a.domain.tld.
The server does not  receive mail
The server does send email out via apache for the websites hosted a  
b.domain.tld and www.c.domain.tld.
Currently when sending out a message on behalf of the hosts named  
above it comes from apache at a.domain.tld

What I would like to do is when apache sends out email it is sent  
from donotreply at b.domian.tld and donotreply at www.c.domain.tld  
respectively. From rereading docs it seems by setting Cw in  
sendmail.cf to a.domain.tld and creating a virtusers table mapping  
the local user apache to donotreplay at each host this should be  
possible.

Is this not possible?
Is my approach correct or is there a simpler/better way to achieve  
this ?
What I'm lost as is how will sendmail know which virtuser to send the  
message out as ?

thanks,
SL

ps: no I can not install a different mail server or OS no matter how  
much either/both pain me.