Re: Fragment flooding in 2.4.x/2.5.x

From: Henning P. Schmiedehausen (
Date: Tue Aug 06 2002 - 02:53:13 EST

Trond Myklebust <> writes:

>>>>>> " " == kuznet <> writes:

> > Hello!
> >> the bug has already been known to crash a few servers...

> > Sorry? What crash do you speak about?

>You'll find it documented on RedHat's Bugzilla (can't remember the
>exact reference - sorry). Basically the first RH-7.3 kernels were
>causing a DOS on a couple of Netapps w/ Gigabit connections.

You didn't exactly need a NetApp for this. A RH 7.3 NFS client with a
Solaris 2.6 NFSv3 server box and a switched, trunked 100 MBit network
was very very sufficient. I have the mrtg printouts still on the wall
in my office. 46 hours of solid 93 Mbits/sec of fragmented NFS packets
chewing off traffic on its VLAN and dropping everything else out of
the backbone trunks. Every service and their grandmothers died around
here. :-)

Ah, the joys of NFS.


Dipl.-Inf. (Univ.) Henning P. Schmiedehausen       -- Geschaeftsfuehrer
INTERMETA - Gesellschaft fuer Mehrwertdienste mbH

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