log visited sites of captive portal users.

Hi,

New laws in europe force us to keep track of our captive portal users.
I've been thinking of adding logrules on dest ports 80,443,22,etc and log
everything to a remote syslog server.
On the other hand we've got quite some hotspots and I'm afraid this will
generate tons of traffic.
Anyone who has worked out a solution already to do this with m0n0wall?


Kind regards
Y