Re: [NFS] nfs-over-tcp still needs udp ports? (SLES 11)

[Aaron Wiebe <epiphani@gmail.com>]

On Thu, May 7, 2009 at 11:35 AM, Tom Talpey <tmtalpey@gmail.com> wrote:
>
> There is one small caveat to using mountproto=tcp through firewalls:
> while the mount will succeed, there are some side protocol exchanges
> which may not.
>
> In particular, if you do NLM file locking, there is a server callback (NLM
> "granted") which the server may choose to issue via UDP. If this callback
> is not seen by the client due to firewall blocking, there may be a 30-second
> pause before a client retry unblocks the caller.
>
> Also, the NSM (status monitor) exchanges are often performed via UDP.
> Again, if you are using NLM and the server reboots, the client may not
> become aware of this promptly, and lock reclaim will be affected.

Sorry for the slight threadjack, but a question along those lines...

My understanding is that currently portmap will not bind any UDP NLM
listeners unless there are UDP mounts on the machine.  I know there
are servers out there that will always speak NLM over UDP
(netapp/ontap being the prominent one), and as a result there can be
problems without firewalls.  If servers are out there that will speak
NLM over UDP regardless of the mount itself, shouldn't we be binding
NLM/UDP regardless of the mount transport?

(Or did I miss this change being reverted a while back?)

-Aaron

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