Re: NFS through firewall

[Philippe Troin <phil@fifi.org>]

Robert Rati <Robert.Rati@motorola.com> writes:

> I am trying to provide a directory to the outside world through a
> firewall via NFS.  I can mount the directory from another system, but
> when I try to list the contents of the directory the firewall blocks
> the communication.  I see that the host system is attempting to send
> data on port 65535 using the UDP protocol.  I have the following
> firewall rule that SHOULD match it, but isn't:
> 
> /sbin/ipchains -A output -j ACCEPT -i eth0 -p udp --source-port 61000:65535
> 
> I have set the local port range to be 61000-65535.  My question is,
> why is NFS choosing port 65535 to transfer data?  Is it using the
> local port range?  I tried changing the port range and restarting the
> NFS daemons, but it still tried to use port 65535.
> 
> I know this isn't necessarily a firewall expert group, but have there
> been any issues with ipchains/2.2 kernels blocking NFS traffic on port
> 65535?

It's a fragment, which will match with -f in ipchains.

Alternately, you may set the net.ipv4_always_defrag sysctl, or (for
2.4), insmod ip_conntrack.

Phil.


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