[rsyslog] Feedback requested "Last message logged n times"...

Rainer Gerhards rgerhards at hq.adiscon.com
Tue Mar 18 12:42:11 CET 2008

Good discussion, thanks all :) ... some more points below ...

> > I have asked the question on a local lug to get some more opinions.
> > will post the results if any here.
> I did the same. :)
> The only arguments against removal I have received until now were:
> 1. DoS  (but nobody explained how)

I think this is along the lines of making it easy to flood the log with
similar messages. If that's the case, I think it is a (too) weak
argument because an attacker could easily include a random pattern
inside the message.

HOWEVER, the current logic indeed prevents flooding the log from equal
messages, e.g. if a process runs wild.

> 2. cleanness of logs (relative)
> I'm thinking about forwarding discussion to fedora-devel :)


Maybe there are also alternatives to the current behavior, something in
between. Right now, the core engine does this, so the reduction
capability is inherent to every action (except if an action specifically
forbids it, because it can not intelligently handle it - e.g. database
writers). So it applies to  forwarding, snmp, whatever, ... One
alternative would be to remove it from the core engine and move it into
the *file write* output plugin (omfile). This has its subtleties, too,
so I don't like to take that approach lightly. Plus, it than means that
the network may become spammed. I think one core requirement is to find
people who actually *intentionally* use this feature and ask for their
reasoning. That will probably be the best way to tell us if its really
needed. And, of course, we need to weigh the negative effects of it
against these con-points.


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