Date: Fri, 29 Apr 2005 12:04:37 -0700 From: "Ted Mittelstaedt" <tedm@toybox.placo.com> To: "Paul Schmehl" <pauls@utdallas.edu>, "Ihsan" <ihsan_junaidi@yahoo.com.sg>, <freebsd-questions@freebsd.org> Subject: RE: FreeBSD mailing list reverse DNS problem Message-ID: <LOBBIFDAGNMAMLGJJCKNMEEAFBAA.tedm@toybox.placo.com> In-Reply-To: <02507140851D7995A5E38D42@utd49554.utdallas.edu>
next in thread | previous in thread | raw e-mail | index | archive | help
owner-freebsd-questions@freebsd.org wrote: > --On Friday, April 29, 2005 03:14:36 AM -0700 Ihsan > <ihsan_junaidi@yahoo.com.sg> wrote: >> >> I've checked and rechecked with internal and external >> name servers which allow foreign queries that my IP is >> resolvable to anggerik.meltechsystems.net (dig -x >> 202.71.100.92) but somehow FreeBSD servers couldn't get the reverse >> information. >> > I checked, and your DNS ids your box as the MX for your domain as > well. > > The first thing I would do is telnet *from* your mailserver to > the FreeBSD > mailserver and try a manual SMTP session and see what happens. If > you get rejected then, you *know* it's a problem with the FreeBSD > server. > > You probably know this already, but just in case: > > % telnet server.freebsd.org 25 > HELO meltechsystems.net > MAIL FROM: you@yourdomain > RCPT TO: list@freebsd.org > > If all this works, then something else is causing the problem. > Paul, that trick doesen't really prove much. Keep in mind that Sendmail routes outbound mail to a destination IP address based on the results of a DNS query. I have seen plenty of problems where for example a domain like freebsd.org lists 2 nameservers, one of the nameservers goes down or starts responding with bogus records. Doing a manual lookup via nslookup gets you an IP address you can telnet into - but your sendmail still won't send mail to the mailhost for that domain. To the uninitiated, the problem appears to be that the destination mailserver is refusing to respond to incoming SMTP from you - rather than your mailserver cannot find the destination mailserver. Ted
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?LOBBIFDAGNMAMLGJJCKNMEEAFBAA.tedm>