From: Ole Holm Nielsen (Ole.H.Nielsen@fysik.dtu.dk)
Date: Mon Mar 13 2006 - 07:17:15 EST
This long overdue summary reports solutions which we have found
recently. The NFS problems originate from turning on the "iptables"
firewall in the Linux NFS client PCs. There are several solutions:
1. Turn off the iptables firewall service on the Linux client.
2. On the Linux client open up all traffic to the NFS server:
iptables -A <rule-name> -s <NFS-server-hostname> -j ACCEPT
On Redhat Linux this can be configured in the /etc/sysconfig/iptables
file. The command iptables-save may come in handy as well.
3. Configure iptables to specifically allow NFS traffic (a royal pain ...).
Some useful links on this topic are:
http://www.faqs.org/docs/Linux-HOWTO/NFS-HOWTO.html#FIREWALLS
http://www.troubleshooters.com/linux/nfs.htm#_disable_firewalls
http://www.troubleshooters.com/lpm/200305/200305.htm#_A_Somewhat_Practical_Server_Firewall
Original question:
> We have an Alphaserver DS25 NFS fileserver running Tru64 UNIX v5.1B
> Patch Kit 4 (we will upgrade to PK5 shortly). In recent months
> we've been having some serious NFS problems on many Linux clients,
> since we started upgrading them to the latest Linux versions
> such as Redhat RHEL 4.0 and Centos 4.1 (all running the Linux
> kernel version 2.6):
>
> Too often the NFS client hangs waiting in NFS I/O on the users'
> home directory, as soon as the user logs in to the graphical
> desktop (GNOME or KDE). Removing the user's GNOME or KDE
> setup and rebooting the NFS client will in many cases solve
> the problem, but the apperance of the problem seems to be
> erratic and irreproducible. If the client is turned off
> for some minutes the problem sometimes goes away, so there
> may be a timeout factor involved. There is nothing in
> the Tru64 server's /var/adm/messages which points to any errors.
>
> Older Linux NFS clients running the Linux kernel 2.4 have
> no such problems with this particular server.
>
> We suspect that some new features in the Linux kernel 2.6
> and/or GNOME and KDE is triggering a bug in the Tru64 UNIX
> NFS server. We have not heard of similar problems with
> Linux NFS servers.
>
> Question:
> Has someone else got experience with Tru64 NFS servers and
> Linux NFS clients (recent kernel 2.6 versions only) ?
> Is there a workaround or patch which solves this NFS problem ?
-- Ole Holm Nielsen Department of Physics, Technical University of Denmark
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