L2Walker is a "Proxy" it intercepts incoming and outgoing packets, and can also falsify either or the real marvel about L2 Walker was the ability to use the OoG bot which meant you did not have to have even a lineage 2 client open. This was done by falsifying packets, but Lineage 2, at least, from my experience was extremely susceptible to packet tampering with little to none server side protection. This lead to a rash of untraceable hackings, because you could literally log into people's accounts using your credentials and the server logged it as you logging onto your account.