[Mimedefang] Revisit: Filtering on HELO

Jeff Rife mimedefang at nabs.net
Sun Mar 25 17:25:41 EDT 2007

On 25 Mar 2007 at 13:26, Philip Prindeville wrote:

> > Actually, if you run tests, you will see that Sendmail uses the host
> > name as the HELO argument unless you use the "h" modifier in
> > ClientPortOptions.  In the latter case, it will use the name of
> > the outgoing interface if it can resolve it.
> >
> >
> >   
> That still goes towards my point, which was that the host
> uses the address of the interface that's outbound for the
> connected socket.

But, *only* if you have changed the default sendmail configuration.

> Remember: the original point was that if a host is
> multi-homed {A.A.A.A, B.B.B.B, C.C.C.C}, that it is
> incorrect behavior to say "EHLO [B.B.B.B]" on a
> socket that is bound to any local interface *other
> than* B.B.B.B.

But the default sendmail configuration when bound to a specific 
interface is *not* to use that interface hostname, but to use the 
"global" (for lack of a better term) hostname, which may not be the 

Although sendmail never uses address literals unless you specifically 
use that as the hostname, I see no reason why it would not use the same 
behavior for address literals as for hostnames.

As long as the hostname or address literal in the "HELO" is a public 
address, then it makes no difference if that name in any way matches 
the interface from which the connection comes.

Jeff Rife | "One minute we were spanking each other with 
          |  meat, and the next minute it got weird." 
          |         -- Joe Hackett, "Wings" 

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