LINUX: ip masquerading

Having seen a Linux box configured as a firewall, using IPCHAINS, I would like to understand what a line like this means:

prot expire source destination ports
TCP 00:12:75 123.100.1.2 205.229.43.186 2348 (62049) -> www

This line comes from the ipchains – L command and is under IP masquerading entries.
Thanks