How to Log IP Address for Inbound Connections in MySQL
If you have shell access to the server on which mysql is running, you can use tcpdump + pt-query-digest. First, do a tcpdump with the appropriate switches necessary for pt-query-digest: tcpdump -i [your interface] port [3306,etc] -s 65535 -x -nn -q -tttt > tcpdump.out

Then, after you are done with your packet capture, do this:

pt-query-digest tcpdump.out --type=tcpdump --group-by=fingerprint --print --no-report

That will give you the raw digest of all queries and the hosts from which they originated. More information can be found at: http://www.percona.com/doc/percona-toolkit/2.1/pt-query-digest.html