Re: [exim] Bogus HELOs

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Autor: Exim User's Mailing List
Data:  
Dla: Gary Allen Vollink
CC: Exim User's Mailing List
Temat: Re: [exim] Bogus HELOs
[ On Tuesday, May 24, 2005 at 16:43:24 (-0500), Gary Allen Vollink wrote: ]
> Subject: Re: [exim] Bogus HELOs
>
> > However the last time I saw, or even heard of, a true multi-homed SMTP
> > gateway (that was not a gateway to a private network (*)) was about 15
> > years ago.
>
> My server, inferno.inside: 192.168.2.4, is also...
> x.x.177.3 (dns) (and ntp, but reverse is for dns)
> x.x.177.16 (mail)
> x.x.177.106 (www)
> x.x.177.111 (webmail)


Given those values your machine is most certainly _NOT_ multi-homed.
Your system simply has several IP alias addresses in addition to its
primary interface address. A multi-homed host sits on multiple
independent networks.

Your mailer's outbound SMTP connections will not (or "SHOULD NOT") get a
different address depending on where they're connecting to (nor should
the available addresses be randomly assigned). No interface alias
address should ever be used as a connection source address unless the
application explicitly binds to that address, in which case the
application knows bloody well exactly what name it should use).

This machine though _is_ multi-homed, but only to two separate private
networks (where XXX.YYY.ZZZ.13 is its public IP address):

$ netstat -in
Name  Mtu   Network       Address              Ipkts   Ierrs    Opkts  Oerrs Colls
pcn0  1500  <Link>        00:60:94:EE:FF:fb 1033609248    25 989218216     0     0
pcn0  1500  XXX.YYY.ZZZ   XXX.YYY.ZZZ.13    1033609248    25 989218216     0     0
fxp1  1500  <Link>        00:02:b3:EE:FF:c0   82316041     2  87116078     2     0
fxp1  1500  192.168.168   192.168.168.1       82316041     2  87116078     2     0
fxp0  1500  <Link>        00:90:27:EE:FF:13   14037196     0  10312495     0     0
fxp0  1500  192.168       192.168.0.5         14037196     0  10312495     0     0
lo0   33220 <Link>                              313776     0    313776     0     0
lo0   33220 127           127.0.0.1             313776     0    313776     0     0


However it's not a mail gateway, just a firewall and the only mail it
sends are internal system reports which are sent to a host with which it
already has a known trust relationship. :-)

-- 
                        Greg A. Woods


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