Hi all,
First of all, I like to wish you all a happy new year! But with business now
being as usual again, I also have a question for you.
On an AS1200 running Tru64 v5.1 (patchkit 3) a couple of services is being
monitored from another host (by connecting the port)
To check whether SMTP is running is connects to the host at port 25, waits
for SMTP's answer header like the following:
Connected to host01.mydom.nl.
Escape character is '^]'.
220 host01.mydom.nl ESMTP Sendmail 8.9.3 (1.1.29.3/15Oct01-0139PM) Wed, 2
Jan 2002 13:29:34 +0100 (MET)
...and disconnects
In syslog.dated/current/mail.log I saw a lot of the following messages:
Jan 2 13:16:23 host01 sendmail[363262]: NOQUEUE: Null connection from
IDENT:root_at_[xxx.xx.xx.xxx]
With 'xxx.xx.xx.xxx' being the server running the monitoring tool its
ip-address.
Reason for the entries in mail.log is the timeout on the connect at port 25.
This sometimes happens. I guess the reason for that is, that host01 tries to
resolve the xxx.xx.xx.xxx hostname. (because he likes to know who's
knocking, right?)
Entries in resolv.conf are correct. Resolving the hostname on the command
line (nslookup) is always very fast. By adding the server's hostname in
/etc/hosts the timeout on the SMTP port no longer occurs.
Why does SMTP has a problem in resolving the hostname (while there is no
problem from the command line)
Besides adding the hostname in /etc/hosts, is there any other way to solve
this?
Thanks in advance for suggestions, hints etc.
Alex Harkema
Vertis unixbeheer
Received on Wed Jan 02 2002 - 13:04:56 NZDT