Amanda-Users

Re: dump to tape failed - how to diagnose?

2004-01-05 14:32:25
Subject: Re: dump to tape failed - how to diagnose?
From: John Dalbec <jpdalbec AT ysu DOT edu>
To: Georg Rehfeld <georg.rehfeld AT gmx DOT de>
Date: Mon, 05 Jan 2004 14:31:18 -0500


Georg Rehfeld wrote:

Hi Kurt, John and all others,

Kurt Yoder wrote:

John Dalbec said:

So the dumper immediately reports 'connection refused' when
attempting
to connect to the taper process. Wrong permissions?


Wrong permissions on what?  It's a TCP connection over the loopback.
What
permissions could possibly affect that?
John

Perhaps a dumb question: did you add the amanda server pieces to
your inetd.conf file and then restart inetd? "Connection refused"
sounds like the amanda server ports aren't open at all.


I guess John has done the (x)inetd part correctly, as his Amanda
setup backs up all other partitions. Only the 'directly to tape'
ones are affected.

In that case inetd isn't involved at all, Amanda starts a taper
and a dumper on the tape-server, the taper tells a listening port
and the dumper attempts to connect to that port on localhost, both
initiated and dumper pointed to the right port by the Amanda driver.

My (wrong) impression was, that one or both of the processes had to
be setuid root, but this isn't neccessary.

 From the dumper message 'Connection refused' one knows, that there
was some process answering to the incoming request on that port and then
actively issuing "no, don't accept you". An inetd misconfig would
result in a timeout, a typical firewall action (of dropping packets)
too.

Firewalls should typically not interrupt communication between 2
processes on the very same box (as of PORT.USAGE).

My current guess is a misconfigured packet filter on the tape host,
but it would be nice, if some network expert jumps into this problem.

regards
Georg

It just occurred to me that maybe this is a side effect of /etc/hosts cache poisoning (courtesy of Red Hat Linux 7.3 NSCD). We've been getting e-mail from a netblock in Vietnam that reverse-resolves to "localhost". NSCD caches the reverse lookup and resolves "localhost" to a machine in Vietnam. Does amanda use gethostbyname("localhost") when connecting a dumper to a taper? Would upgrading to the current version change this?
Thanks,
John