I’d like to have my DD-WRT router keep a log on my server, rather than in it’s memory. Ubuntu’s rsyslog service does that. Here are the changes needed:
Modify the rsyslog configuration file

Using your favorite text editor, edit a new file named /etc/rsyslog.d/60-remotelogging.conf
Add the following to enable the UDP listening service:

# Begin /etc/rsyslog.d/45-remotelogging.conf
# Enable remote logging server
$ModLoad imudp
$UDPServerRun 514

# Send all logging from DD-Wrt router to a specific log file.
if $fromhost == 'router.home' then /var/log/ddwrt-syslog
& ~

# End /etc/rsyslog.d/45-remotelogging.conf

Now restart the syslog daemon

sudo service rsyslog restart

Now I just need to figure out how to analyze it :D.