SUMMARY: Sendmail problem

From: Jae An (
Date: Tue Aug 11 1998 - 22:37:36 CDT

> Hi everybody,
> For the past 2 months one of the systems in our domain (SPARCstation 1+
> running SunOS 4.1.3_U1) has problem sending mail in certain hosts.
> It does not seem to have problems with any of the .edu, but users
> can not send email for example at (they used to do it all the
> time 2 months ago -- it is not only aol, but also other .com addresses
> -- not all of them though). Similarly configured machines in
> the same domain do NOT seem to have any problems.
> Example problematic mail message to AOL from host:
> ----- The following addresses had permanent fatal errors -----
> ----- Transcript of session follows -----
> ... while talking to
> >>> MAIL From:<user@hostname> SIZE=39
> <<< 550 <user@hostname>... Sender domain not found in DNS (see RFC 1123, sections 5.2.2 and 5.2.18).
> 554 Service unavailable
> Using the verbose mode of `mail' I get the following warning message, when
> sending mail to any address:
> WARNING: local host name (hostname) is not qualified; fix $j in config file
> How do I eliminate it?
> Is this the source of the above non-delivery problem?
> If yes, how come it affects only certain cases?
> Please let me know if you need additional info.
> Thanks.

The computer was reconfigured, by changing its hostname to:
`' instead of just `hostname'. Then the
mailer was restarted, and that took care of it.

In the battle to fight spam, more and more sites are now qualifying
who they receive mail from. Some are just looking for a valid
'style' of sender (i.e. would work) others are now
doing DNS (Domain Name Service) lookups on the domain to see if
it can be resolved to an IP (Internet Protocol) address, and some
then compare the IP address from the DNS lookup to the IP address
the connection is coming from.
If whatever check they are using fails, they refuse to
accept the email. The reason our problem started recently, and
appeared only with certain hosts is that an increasing number of
large sites every day add these measures to protect themselves
from annoying email that floods people's mailboxes.

Thanks to:
Claus Assmann <>
Craig Raskin <>
Sebastian Benoit <>
Frank Smith <>
Kristian Forde <>
Vince Hickey <>
Bismark Espinoza <>

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