trace route the server, a good app for that can be
UOtrace, there are others.
its most likely a hop to the server that is bad, or your
isp could be bad if its shared bandwidth.
there's really nothing you can do but call and complain
to the source of your problem. example, if its your
isp, call them. if its a hop and not your isp, identify it
and get their phone number from whois.com or whatever
whois service you use.
from there, b1tch and whine and call often, lag will go away if you do it long enough.
