Re: tlug: External DNS woes

["Scott M. Stone" <sstone@example.com>]

On Thu, 11 May 2000, Chris Sekiya wrote:

> On Thu, May 11, 2000 at 01:40:10PM +0900, Stephen J. Turnbull wrote:
> 
> > I'm having trouble with mail being intermittently refused from various
> > sites because "Sender domain must exist."
> 
> ... basic anti-spam measures added during the 8.9.x era check the SMTP envelope
> from: address.  If it doesn't resolve, it fails the test.  If you're behind
> a firewall, sending from a machine that doesn't have a lookup, it's going to
> fail.
> 
> This is fixed by adding the following to your .mc:
> 
> MASQUERADE_AS( {your externally-visible MX} )dnl
> FEATURE(masquerade_envelope)dnl
> 
> ... so, no matter how badly your network admins botch things, mail should
> still go through ...

Or just add (assuming your externally visible MX is foo.com):

DMfoo.com

into sendmail.cf.  That way you don't have to rebuild from m4.  although
knowing the m4 is handy.  thanks Chris!

--------------------------
Scott M. Stone, CCNA <sstone@example.com>
UNIX Systems and Network Engineer
Taos - The SysAdmin Company 

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