On later versions of Ubuntu, the /var/log/messages is not on by default.
Since I use it for some applications, here are the steps I used to enable it:
Edit the file /etc/rsyslog.d/50-default.conf and uncomment the four lines:
(starts at line #38 on the current system I’m working on, Ubuntu 12.04)
*.=info;*.=notice;*.=warn;\
auth,authpriv.none;\
cron,daemon.none;\
mail,news.none -/var/log/messages
Then restart syslog like this:
restart rsyslog
That’s it – /var/log/messages should now be there, just like the good old days!