Log files, and rotation

Hi. My /var/log/messages doesn’t seem to be to be changing - it’s just stayed one file that continues to grow. Is it expected that the /messages log won’t rotate? Other files (syslog, for ex) do switch out. Is there a setting/configuration that I might have turned off (or never turned on), that I should look for, if it is supposed to roll over?
As a minor irritation, can I change what gets sent to the /messages? Every single time my nic enters/leaves promiscous mode, it’s logged - I’d swear it’s 40-ish percent of the logged lines, lol.