Total freezeup under network load

[David]

Hello,

I've encountered a problem with FreeBSD. When I upload files to my FTP server
(pure-ftpd v1.0.18) on the LAN I get speeds around 3MB/s. Then, suddenly and
at totally random times, the transfer stops. If I'm connected to the server's
IRCd I ping timeout. The server totally freezes for a period of 5-10 seconds
or so. I've tried using two different clients, both give me this result. Even
if there's a problem with the FTPd, the OS/network shouldn't freeze up
totally. The computer in question has a VIA 533MHz board, with an on-board NIC.

I tried asking for help on IRC (#freebsdhelp on EFnet), but it seemed like no 
one had ever encountered this problem before. An op told me to look into 
dummynet. I guess enabling dummynet in the kernel could aid me, but I still
think that it's strange that FreeBSD locks up after a random period of time,
after being under a network load. I would really appreciate help on this.
Thanks.


/David