[syslog-ng] Resolving Hostnames for Syslog Source IPs

Jarrod Manzer jmanzer at godaddy.com
Wed Jun 1 18:33:58 CEST 2005

I had this same problem. I resolved it by logging by IP and then doing 
reverse DNS lookups with a script and creating symbolic links to those 
IP based directories. The end result was people who like to use IP or 
DNS were happy. Gotta make sure your reverse is set up properly though.

But I never did find out why syslog-ng couldn't resolve the same names 
that the host command on the same box could.

Sawall, Christopher L wrote:

>I used to only log by IP and was fine with it.  But with a recent acquistion and to make things easier, I turned on the use of DNS by Syslog-NG.  However, it doesn't appear to resolve every source host.
>For example, I am sending syslogs from about 50 sets of Cisco PIX firewalls, 5 VPN Concentrators and 2 Cisco Cache Engines.  Only about 80% of the PIX firewalls are being resolved when they show up in the syslog file, 2 of the concentrators and none of the cache engines.  I have verified that all of the firewalls are in DNS and PINGable from the syslog server itself.
>I'm not sure what else to check.  I saw an old post from September 2003, but I don't think it's the same issue.  This appears to be a consistent problem, some hosts are always resolved and some are not.
>Below are the options that are set in my syslog-ng.conf file.
>options { sync (1);
>          time_reopen (10);
>          log_fifo_size (2048);
>          long_hostnames (off);
>          dns_cache(yes);
>          use_dns (yes);
>          use_fqdn (no);
>          create_dirs (no);
>          keep_hostname (yes);
>        };
>source src { unix-stream("/dev/log"); internal(); udp(ip( port (514)); };
>Let me know if any other info would be benenficial.  
>Chris Sawall, GSEC, GSNA
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.Jarrod  Manzer.
.Network   Team.
.Go Daddy Group.
.(480) 366 3631.
.AIM:  nejarrod.

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