Trying to debug problems with consumer-grade routers is notoriously difficult due to a lack of decent debugging information. It's quite hard to know what's going on without at least a few good error messages.

Here is how I made my OpenWRT-based Gargoyle router send its log messages to a network server running rsyslog.

Server Configuration

Given that the router (192.168.1.1) will be sending its log messages on UDP port 514, I started by opening that port in my firewall:

iptables -A INPUT -s 192.168.1.1 -p udp --dport 514 -j ACCEPT

Then I enabled the UDP module for rsyslog and redirected messages to a separate log file (so that it doesn't fill up /var/log/syslog) by putting the following (a modified version of these instructions) in /etc/rsyslog.d/10-gargoyle-router.conf:

$ModLoad imudp  
$UDPServerRun 514  
:fromhost-ip, isequal, "192.168.1.1" /var/log/gargoyle-router.log  
& ~

The name of the file is important because this configuration snipet needs to be loaded before the directive which writes to /var/log/syslog for the discard statement (the "& ~" line) to work correctly.

Router Configuration

Finally, I followed the instructions on the Gargoyle wiki to get the router to forward its log messages to my server (192.168.1.2).

After logging into the router via ssh, I ran the following commands:

uci set system.@system[0].log_ip=192.168.1.2  
uci set system.@system[0].conloglevel=7  
uci commit

before rebooting the router.

Now whenever I have to troubleshoot network problems, I can keep a terminal open on my server and get some visibility on what the router is doing:

tail -f /var/log/gargoyle-router.log
Log Rotate

One other thing you might want to add is to add /var/log/router.log to /etc/logrotate.d/rsyslog so that it doesn't grow forever.

Cheers, -m

Comment by max