[CentOS] sendmail / logwatch relaying issue - driving me crazy

Thu Dec 23 13:30:29 UTC 2010
Les Mikesell <lesmikesell at gmail.com>

On 12/23/10 3:44 AM, Götz Reinicke - IT-Koordinator wrote:
> Hallo, *<:-)
>
> may be I'm to tired to see the solution, maybe someone can give me a hint?
>
> I do have a couple of servers, sending the daily logwatch report to a
> central support email account.
>
> Some servers do have DNS A and CNAME records. On my mailserver relaying
> for the servers is allowed.
>
> Only one server drives me crazy, getting user unknown or releaying
> denied messages.
>
> Any idea, how to debug this issue? I'd be glad to fix this as a
> christmas gift. I could provide logmessages of course.
>

If there is an MX record for the target address, it will go there instead of to 
the A record for that name.   The receiving server will usually try to resolve 
the From: host address and reject if it can't, so the sender must have a valid 
hostname in your DNS (or turn off that feature).  If the receiving server 
doesn't accept for the target domain/host address you'd get the relaying denyed 
error.  If it does accept for the domain but does not have the user in the 
address you'd get the user unknown error.

-- 
   Les Mikesell
     lesmikesell at gmail.com