Speed Issues through NAT Firewall

[Travis Crook]

Hello,     I currently have two firewalls running.  Both on Mandrake 8.1 running iptables.  I currently have two internet connections (one is a DSL line at 1Mb, the other is straight from an ISP at 2.5 Mb).  I can get 700Kb speeds through the firewall on the DSL line (which is about as fast as it ever is) but I only get about 500Kb speeds through the firewall on the ISP line.  Shouldn't I be able to get at least 2Mb speeds through this firewall?   Thanks   Travis Crook Visions Beyond