Internal Network Transfer Problems

[Dan Serban]

I am realtively naive when it comes to netfilter and I am looking for a little bit of help.  I downloaded hpfirewall.tgz from http://herbie.espong.org/filez/iptables/ and installed the example script successfully.  This seems like quite a secure setup based on others attempts.  All external accesses (computers on the internal net accessing external internet resources) work perfectly fine, HTTP, FTP, SSH etc...  I have two boxes behind the firewall machine and I've tried tranferring files between the two machines unsuccessfully.  Any smb accesses between the two machines start out fine but tend to crap out within a couple of minutes, I can browse the Linux box from the Win98 box through Samba, but any file operations fail within a few seconds/minutes.  I've also setup FTP services on both machines and each connects to the other immediately, after which point when I start a file transfer of anything larger than 64k, the transfer slows down and eventually slows down to a crawl and stops.  Because of the fact that I've installed such a large script I cannot even begin to diagnose the problem here.  I can access the firewall machine through SSH from both the Win98 machine and the Linux machine with no problems.  The only thing that I've noticed of significance between the two is that when either SMB or FTP access occur between the two internal machines, the collision light on the hub comes on with pretty much each packet (link activity).  Can someone please help me here?  Maybe where I should begin looking through the aforementioned script?  Or another script I can use to replace the current one?  As a side note, I've also tried David Ranch's rc.firewall-2.4-stronger script and I experience the exact same issue.   Thank you!   Dan