svn commit: r197298 - head/sbin/mount_nfs

[M. Warner Losh]

In message: <Pine.GSO.4.63.0909201722330.22125 at muncher.cs.uoguelph.ca>
            Rick Macklem <rmacklem at uoguelph.ca> writes:
: 
: 
: On Sat, 19 Sep 2009, M. Warner Losh wrote:
: 
: > :
: > : Hmm, it might actually be nice to be able to change those at some point
: > : as well.  I have looked at this in the past and it is quite deeply
: > : buried in libc. :-/
: >
: > What's the benefit for forcing a tcp connection for the portmapper
: > RPCs?  They just happen once at startup...
: >
: Someone mentioned an issue w.r.t. umount using UDP, which was basically
: a slow timeout when a server didn't handle the UDP call, such as when
: it was down. I'd guess that a TCP attempt would fail more quickly than
: a UDP attempt when the server doesn't have rpcbind/portmapper running.
: (Not so sure when the server has crashed, but I'm guessing that the TCP
: connection attempt fails more quickly than the N retries over UDP?)

A server down would have the same timeout issues as a UDP timeout.

: And what about going through NAT gateways? (I'm not familiar with how
: typical NAT gateways are set up, but do they all forward UDP ok?)
: 
: I suspect others would know more about the tradeoffs? rick

I think Sam hit the nail on the head: Its more firewall friendly to be
able to do it...

Warner