I recently changed the OS running an Ultima Online server from Win 2k Server to Linux. Since that, the gameplay started lagging a lot more than normal, getting worse by the minute. The ping before I run it is around 140ms, and after, it's really inaccurate:

Resposta de x.x.x.x: bytes=32 tempo=818ms TTL=50
Resposta de x.x.x.x: bytes=32 tempo=170ms TTL=50
Resposta de x.x.x.x: bytes=32 tempo=242ms TTL=50
Resposta de x.x.x.x: bytes=32 tempo=242ms TTL=50
What can I do to get the server to run well? The machine and connection is the same as when we ran Win2k.

The server also shuts down by itself, and constantly complains about Tx errors and Main Loop freezing, which didnt happen before the OS change.

One third thing (doesnt have to do with Linux) that screws our server a lot are occasional DoS attacks (mainly from banned users and their friends). It's a brazillian server, and everyone here seems to know how to perform one. What could I do to minimize these attacks? Authorities here don't seem to care much about internet crimes.

Sphereserver 55i R4.02 (Red Hat 9)