Linux hangs when net too used

[Conrado Badenas <Conrado.Badenas@uv.es>]

Hi all!

I've been having problems with Linux the last months, but now I have
isolated the problem: Linux hangs.

1) I thought it was the kernel but it hangs with 2.0.34, 2.0.35 and
2.2.1
2) Then I thought it was the memory but memtest (package sysutils) says
it is OK.
3) Then I thought I was being attacked with a DNS, but I read about them
and kernel 2.2.1 should stop teardrop, winnuke, etc.
4) Then somebody told me that maybe only X hanged and I could access my
machine from outside: I checked that I couldn't telnet/ftp/http my
machine from outside
5) Now, one of my users connected from outside via ftp and began
uploading a file of more than 3 Mb. He tried it three times, and my
machine hanged three times (one hang, one boot, one hang, one boot, one
hang, one boot, I denied access to this user, no hangs)

WHAT IS HAPPENING? I love Linux but my friends laugh at me when I tell
them that Linux hangs.

-- 
Conrado Badenas (Assistant Lecturer)
Department of Thermodynamics. University of Valencia
c/. Doctor Moliner, 50       | e-m: Conrado.Badenas@uv.es
46100 Burjassot (Valencia)   | Phn: +34 - 963 864 350
SPAIN                        | Fax: +34 - 963 983 385