[syslog-ng] FQDN's in syslog-ng

Stenglein, David David.Stenglein at deshaw.com
Thu Aug 24 23:19:47 CEST 2006

Russell and Steven,

There are problems with trying to use macros, as you have found. There
is a good bit of detail on this page (part of the FAQ, I believe)

The problem I had was that I started to get strange directory names,
like "cd .." and "::". All sorts of garbage. The reason? The Sun syslog
service produces non-RFC compliant network packets. The packet is
supposed to have the hostname twice, and then the ID field. Syslog-ng
can deal with the second host not being there, but if it is missing the
square brackets, there is no way for it to figure out where the message

So, you can use HOST_FROM and FULLHOST_FROM in your file output.
Syslog-ng then logs everything very neatly, which is what the doc says.

That's all well and good, but what about your remote hosts that have a
forwarder in between? Sun syslog won't work for this anyway (doesn't
handle the origin name correctly), so you use syslog-ng. Fine. But now
you can't use _FROM macros, since that will be wrong too. 

What you will need to do is have the remote syslog-ng forwarders sending
to the central loghost over a separate port (might as well be TCP).
Last, you will need a separate parallel set of rules that use FULLHOST
instead of FULLHOST_FROM in the output path when the source is a remote
syslog-ng server (which will forward correctly formatted messages).

Did I mention timestamps? ;-)


-----Original Message-----
From: syslog-ng-bounces at lists.balabit.hu
[mailto:syslog-ng-bounces at lists.balabit.hu] On Behalf Of Russell Fulton
Sent: Thursday, August 24, 2006 4:18 PM
To: Syslog-ng users' and developers' mailing list
Subject: Re: [syslog-ng] FQDN's in syslog-ng

There are a several of different options for dealing with host names and
I have not managed to sort them all out yet.  The single line
explanations in the manual are not enough to work out the details.

Be aware that the hostname can be set on either the central log server
or on the system generating the logs.  The default seems to be that the
central server will keep the host name that is in the packet, if there
is no hostname in the packet it will do a reverse lookup to determine
it.  We want to override this but have not spent a lot of time fiddling
with the options to see what works.

What you want to do is possible it just a matter of figuring out which
options you need on the client and server.

What is bothering us at the moment is that SUN monitoring crap called
SRS manages to generate some syslog records with SRS in the hostname
field.  So on the central server these all turn up in the same file.

I really must sort this out today, sigh...

I'd be happy to hear from someone who has already sussed out how these
options work!


Steven Hajducko wrote:
> Hi everyone,
> We've currently got a syslog setup that centralizes our logs from many
> of our different teirs into one location, using each system's prebuilt
> syslog.  It works at the moment, but we've got some issues.
> Our main one is that we name our hosts the same in different
> environments, mainly because these environments are for moving code
> configs from 1 step to the next, so to make it easier on people so
> don't have to change configurations each time the code moves, hosts
> share similar names.
> The problem is that when all the logs come back to the central syslog
> server, they can't be seperated by host because of the similiarities. 
> So 'web5' in our QA is the same as 'web5' in production.
> Because of that, we were looking at syslog-ng and while I found a
> references to using FQDN, I've been unable to tell whether or not this
> is possible.
> Our machines DO have different FQDNs.  For example,
> web5.qa.location.domain.com vs. web5.prod.location.domain.com.  If we
> run our main central server on syslog-ng and replace all the syslog
> daemon's on each system with it, can we force the FQDN to be given
> rather then just the base hostname and have the central log server
> the logs into different directories based on the FQDN?
> Thanks!
> -- 
> sh
> _______________________________________________
> syslog-ng maillist  -  syslog-ng at lists.balabit.hu
> https://lists.balabit.hu/mailman/listinfo/syslog-ng
> Frequently asked questions at http://www.campin.net/syslog-ng/faq.html
syslog-ng maillist  -  syslog-ng at lists.balabit.hu
Frequently asked questions at http://www.campin.net/syslog-ng/faq.html

More information about the syslog-ng mailing list