Subject: Re: Networking (??) problems
To: Jukka Marin <>
From: Brian Buhrow <>
List: current-users
Date: 08/02/1996 08:58:49
	I often see problems with those sorts of things when people at the 
receiving end run tcp_wrappers and the tcp_wrappers on the receiving end
cannot resolve the IP address of the sending host.  In these cases, using
another machine at a different IP address is not a valid test.  What you
need to do to prove that it is a NetBSD specific problem is to configure a
machine with the same IP address at the same location as the problematic
machine and try to make the same connection.  More and more sites are
running tcp_wrappers configured to not accept connections from host ip
addresses they can't resolve, so the problem appears to be getting worse
for those people who run routing gateways in their houses and who don't
keep the publically DNS tables accurately informed.


On Aug 2,  4:05pm, Jukka Marin wrote:
} Subject: Networking (??) problems
} Dear All,
} I have been seeing weird problems on NetBSD systems during the last.. um..
} 6 months or so.  Mostly, the problem shows up with failing mail transmission.
} The messages sit in the queue and are finally returned to the sender with an
} error message.  'mailq' reports problems like "reply: read error" and
} "timeout while waiting for input".
} The weird thing is that this seems to happen _every time_ someone sends
} e-mail to a certain place.  I first thought the receiving systems were
} failing, but if I send the same message from a stunos machine, it gets
} through just fine.  If I use a stunos machine as a gateway, everything
} works well, too.
} Once I used telnet to connect to a remote machine and "sent" some mail
} manually and it worked.  At the same time, sendmail was failing.
} One user whined today that he couldn't get files from our system using
} ftp.  His machine (a linux box) says "connection reset by peer" and
} "remote host has closed connection".  I can't see any problems at my end
} (ftpd works just fine for me).  I just thought this and the mail problem
} could be related.
} Has anyone seen any problems like these?
} I'm running 960413 kernels now, but the problem was there even before.
} I think I'll try upgrading one system and see if it helps with the mail
} problems.
}   -jm
} -- 
}                      ---> <---
>-- End of excerpt from Jukka Marin