Syslogd configuration



I would like to use syslogd for my logging, right now I am doing that by activating syslogd and it does start.

I can see logs on /var/log/messages.

but, it keeps only two “generations” of logs

ls -l /var/log/messages*
-rw------- 1 root root 37867 May 5 18:11 /var/log/messages
-rw------- 1 root root 205059 May 5 18:10 /var/log/messages.0

how can I keep more? which configuration file should I change and what is the correct setting for that ?

thank you