[lug] standalone sendmail

[Hugh Brown]

On Wed, Nov 21, 2007 at 03:19:07AM -0800, karl horlen wrote:
> I've got stock sendmail installed on a vanilla CentOS
> 5 system.
> 
> The system lives behind a dsl firewall and does not
> have a real domain registered in DNS.  I don't want it
> to.
> 
> I'd like the system to email logwatch messages
> normally destined for root to go to an external email
> alias account as specified in /etc/aliases.  
> 
> It sort of works sometimes.  But it obviously is
> getting hung up by the target MTA which specifies
> error messages correctly that:
> 
> "the Domain of sender address does not exist"
> 
> I'm not a sendmail expert at all.
> 
> Is there any way to get around this spam prevention
> technique by many MTAs if you don't have a registered
> domain and separate mail account at an ISP to route
> through?
> 
> Can I relay mail via a "known" email host?  If so how?
> 
> If I have access to a registered domain that is
> already being used for another server on a completely
> different network, can I specify the domain of this
> host to belong to that domain in some way to make it work?
> 

Set up the local box to be a smart relay and the remote box to allow relay from the local box.

If the remote box is sendmail/CentOS then you'd edit /etc/mail/access and follow instructions in that file.  For the local box, edit /etc/mail/sendmail.mc and search for SMART_HOST, uncomment and edit appropriately.

Run "make -C /etc/mail" after you are done.

Hugh