strange network problems

["Avery Pierce" <apierce camteq net>]

Im using a PII 350 with 2 SMC 1211TX Nics (realtek 8139).  Its used for a firewall / NAT Gateway with 1 pc behind it.  If im uploading a file on the firewall my pc behind the firewall had no internet access on tiemouts.  I get heavy packet loss when I ping an outside server..like google.com.  When uploading from my pc through the firewall everything works just fine.  Downloading also works fine.  Im logging all dropped packets with iptables and nothing is behind dropped.  There isnt any errors in /var/log/messages pertaining to the network interfaces.  ive tried updating anything that might be causing this.

System:
Redhat 7.2 Enigma
Kernel 2.4.18-17.x
Nic Driver 8139too 
iptables 1.2.5-3

I connect to the internet with a SurfBoard sb4100 cablemodem through Adelphia.
My pc connects to the firewall using a crossover cable.  My pc has an smc 1211tx nic also.
Any ideas would be appreciated.  Thanks in advance.

Heres an ifconfig on the firewall

eth0      Link encap:Ethernet  HWaddr 00:E0:29:1D:98:6E 
          inet addr:192.168.200.1  Bcast:192.168.200.255  Mask:255.255.255.0 
          UP BROADCAST RUNNING MULTICAST  MTU:1500 Metric:1 
          RX packets:35202 errors:6 dropped:0 overruns:0 frame:0 
          TX packets:24688 errors:0 dropped:0 overruns:0 carrier:0 
          collisions:0 txqueuelen:100 
          RX bytes:2402686 (2.2 Mb)  TX bytes:2912915 (2.7 Mb) 
          Interrupt:5 Base address:0xc000 
 
eth1      Link encap:Ethernet  HWaddr 00:E0:29:95:60:60 
          inet addr:X.X.X.X  Bcast:255.255.255.255  Mask:255.255.255.0 
          UP BROADCAST NOTRAILERS RUNNING  MTU:1500  Metric:1 
          RX packets:26893 errors:0 dropped:0 overruns:0 frame:0 
          TX packets:35608 errors:0 dropped:0 overruns:0 carrier:0 
          collisions:0 txqueuelen:100
         RX bytes:3045857 (2.9 Mb)  TX bytes:2968880 (2.8 Mb) 
         Interrupt:10 Base address:0xe000 

Avery Pierce
Camteq Professional Systems
www.camteq.com