I have a school district that is being plagued by irratic behavior in surfing, 504 gateway timeouts, blank screens...some workstations get out, some don't...very frustrating issue! We had an packet loss issue at first but have corrected that
I am new to the system and trying to figure out the setup. Can you help me out? Here is the current setup (different than what I am used to):

the BorderManager 3.9sp2 server is setup inside the firewall with 2 NICs let's say x.x.x.2 for internal and x.x.x.5 for external. both NICs are connected to the switch (my previous experience would have the external connected directly to the DSL connection) so it is throwing me for a loop...
There is a Linux box firewall x.x.x.3 in front of the router/gateway x.x.x.8.

I'm not fully understanding the setup in BM. Can you walk me through how this should be setup if you have time?

we do not have NAT enabled. Should I have filters enabled? Can I reset the filters to default to fix the slow, irratic problems with internet?

any help is appreciated.