I am thinking on how to come this by on the protocol basis, but so far I
have no good clue (except that Baszi is probably right and it is a
purely operational issue). However, I know some problems in this
relation and though it is not a deadlock issue, I would like to share
the scenario for sake of completeness:
It occurs on a typical *nix system that runs both syslogd and the dns
daemon. So it could potentially occur on almost all *nix DNS servers.
The problem exists if syslogd contains rules for remote forwarding AND
these rules do contain hostnames which need to be resolved by DNS. A
typical problem is that syslogd starts before the dns daemon. When it
intend to send a message to the remote host, it must do a dns lookup,
which fails because dns daemon is not yet active. The stock linux
syslogd contains some logic which simply defers the connection request,
but at the cost of some message loss. Other ways to avoid this problem
is to use IP addresses in syslog configuration, host files or, as Baszi
said, special configuration options for static address mapping in
syslgod.
I do not, however, know actual deadlock situations (that is neither
syslogd nor dnsd can proceed because they are waiting on each other). I,
too, would appreciate any details on that.
Rainer
-----Original Message-----
From: Sam Hartman [mailto:hartmans-ietf(_at_)mit(_dot_)edu]
Sent: Thursday, February 01, 2007 2:09 PM
To: Mark Andrews
Cc: IETF-Announce(_at_)mit(_dot_)edu; syslog(_at_)ietf(_dot_)org;
ietf(_at_)ietf(_dot_)org
Subject: [Syslog] Re: Last Call: draft-ietf-syslog-protocol (The
syslogProtocol) to Proposed Standard
"Mark" == Mark Andrews <Mark_Andrews(_at_)isc(_dot_)org> writes:
>> - 'The syslog Protocol ' <draft-ietf-syslog-protocol-19.txt> as
>> a Proposed Standard
Mark> draft-ietf-syslog-protocol-19.txt recommends using a
Mark> reliable protocol. Existing implementations of syslog do
Mark> this and deadlock with nameservers which are logging via
Mark> syslog.
Please explain the deadlock in more detail. One of the primary
reasons for the syslog working group is reliable syslog, so I think we
need to focus on how to avoid the deadlock in other ways rather than
avoiding reliability.
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