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Date:      Tue, 18 Jul 1995 10:17:49 -0500 (CDT)
From:      faulkner@mpd.tandem.com (Boyd Faulkner)
To:        mikebo@tellabs.com (Mike Borowiec)
Cc:        questions@freebsd.org
Subject:   Re: FBSD v2.0.5: NFS to multi-homed server broken?
Message-ID:  <9507181517.AA28706@olympus>
In-Reply-To: <m0sXz9I-000jBzC@tellab5.lisle.tellabs.com> from "Mike Borowiec" at Jul 17, 95 06:00:23 pm

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> 
> Greetings -
> I have found some anomolous NFS behaviour in FreeBSD 2.0.5R.
> 
> Problem 1:
> FreeBSD attempts to NFS mount a partition from a multi-homed server not
> on the same ethernet, and the return route from the server to the FreeBSD
> client is via another interface (with a different hostname and IP address).
> If done manually, the mount command can be killed. If the mount is in the
> /etc/fstab file, the machine hangs on startup and must be reset.

Been there, done that.  You need the noconn option.  This way, when it comes
back along a different route, there is not a connnection already in force.
I think this is the -c option if you use mount_nfs directly.  Anyway, 
-o noconn solved the problem for me.

> 
> Problem 2:
> Worse yet, the mount succeeds and the route from the server to the FreeBSD
> client is subsequently changed when the server receives a RIP update from
> its router. In this case, any session accessing the affected partition
> hangs and can't be recovered. In some cases, the whole OS runs off into
> the bushes and there's no keyboard response at all... big, red switch time!

I got a session hang if I attempted to access the partition.

> 
> On comp.os.bsd.freebsd.misc I've had people suggest that I not run routed
> on the server. Unfortunately, it will not always be possible for a FreeBSD
> user to dictate this to admin staff, especially when local SunOS machines
> flawlessly handle both of the situations listed above.
> 
> Questions refering to the Sniffer data below:
> o  Trace 1 shows everything works fine if you're sure which interface
>    the server will use to talk to the client... if not...
> o  Trace 2 shows that the SunOS 4.1.3 portmapper returns the proper port
>    number for NFS (2049), but FreeBSD complains that Port 797 is
>    unreachable. How did it get 797 from 2049?
> o  Trace 3 shows that SunOS NFS clients don't bother to portmap the NFS
>    port number which is already well known to be 2049. Why does FreeBSD
>    bother to do this apparently useless step?
> o  Trace 3 shows that SunOS is not bothered by the fact that the responses
>    are from another IP address. It seems to know that the two addresses are
>    in fact the same machine. How, and why doesn't FreeBSD do the same?
> o  Trace 3 shows that SunOS does an apparently useless "Null command"
>    which is ackowledged by the server... why?
> o  SunOS is apparently unbothered when the route from server to client
>    changes, while FreeBSD hangs. How does SunOS handle this and can a
>    similar method be enployed in FreeBSD? 
> 
> Anyone have any info on these problems and whether they will be resolved
> in 2.1R? Thanks...
> - Mike
> 
> Sniffer Network Analyzer data:
> Note that TELLABK and SUNK are different interfaces on the same SunOS
> 4.1.3 server... both of these networks are connected to a router. Both
> TOYBOX and GENESIS are on the same ethernet, which is also connected
> to the same router...
> 
> 	+---------------+
> 	|TELLABK / SUNK |
> 	+---+--------+--+
>             |        |
> 	 =======   ====
> 	    |       |
> 	+-----------+--+
> 	|    ROUTER    |
> 	+-----+--------+
> 	      |
> 	================
> 	   |        |
> 	+--+----+ +-+----+
> 	|genesis| |toybox|
> 	+-------+ +------+
> 
> Successful mount by FBSD 2.0.5 client of SunOS 4.1.3 server:
> toybox# mount sunk:/export/home/tellabk-4 /home/tellabk-4
> 
> Destination Source     Summary
> tellabs     toybox     DNS C ID=1 OP=QUERY NAME=sunk
> toybox      tellabs    DNS R ID=1 STAT=OK NAME=sunk
> sunk        toybox     PMAP C Get port PROG=100003, VERS=2, IP=17
> toybox      sunk       PMAP R PORT=2049
> sunk        toybox     PMAP C Get port PROG=100005, VERS=1, IP=17
> toybox      sunk       PMAP R PORT=733
> sunk        toybox     MOUNT C Mount /export/home/tellabk-4
> toybox      sunk       MOUNT R Mount OK F=075B
> 
> 
> Unsuccessful mount by FBSD 2.0.5 client of SunOS 4.1.3 server:
> toybox# mount tellabk:/export/home/tellabk-4 /home/tellabk-4
> 
> Destination Source     Summary
> tellabs     toybox     DNS C ID=1 OP=QUERY NAME=tellabk
> toybox      tellabs    DNS R ID=1 STAT=OK NAME=tellabk
> tellabk     toybox     PMAP C Get port PROG=100003, VERS=2, IP=17
> toybox      sunk       PMAP R PORT=2049
> sunk        toybox     Port 797 unreachable
>                        ICMP Destination unreachable (Port unreachable)
> tellabk     toybox     PMAP C Get port PROG=100003, VERS=2, IP=17
> toybox      sunk       PMAP R PORT=2049
> sunk        toybox     Port 797 unreachable
>                        ICMP Destination unreachable (Port unreachable)
> ... ad infinitum ...
> 
> Successful mount by SunOS 4.1.4 client of SunOS 4.1.3 server:
> genesis# mount tellabk:/export/home/tellabk-4 /home/tellabk-4
> 
> Destination Source     Summary
> tellabs     genesis    NIS C Lookup key suntell.hosts.byname
> genesis     tellabs    NIS R OK
> tellabs     genesis    NIS C Lookup key suntell.protocols.byname
> genesis     tellabs    NIS R OK
> tellabk     genesis    PMAP C Get port PROG=100005, VERS=2, IP=17
> genesis     sunk       PMAP R PORT=733
> tellabk     genesis    MOUNT C Null Command
> genesis     sunk       MOUNT R Null Command OK
> tellabk     genesis    MOUNT C Mount /export/home/tellabk-4
> genesis     sunk       MOUNT R Mount OK F=0733
> 
> --
> --------------------------------------------------------------------------
> Michael Borowiec        Network Operations      Tellabs Operations, Inc.
> mikebo@tellabs.com                              1000 Remington Blvd./MS109
> 708-378-6007  FAX: 708-378-6714                 Bolingbrook, IL, USA 60440
> --------------------------------------------------------------------------
> 


-- 
_______________________________________________________________________

 Boyd Faulkner - faulkner@isd.tandem.com - http://cactus.org/~faulkner
_______________________________________________________________________



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