NFS Client mount using UDP (187 Views)
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Brian Reiter
Posts: 303
Registered: ‎03-04-2004
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NFS Client mount using UDP

Hi Folks,

 

The system we have is

 

Clustered 2x RX2800s OpenVMS 8-4, Update 7

TCPIP 5-7 ECO 3

 

The system hosts an NFS share (on 1 node) where there may be IP aliases on that network card. There have been an instances where the client performs an NFS mount using the UDP protocol on 1 address and gets a response from one of the other active aliases. For example:

 

 

   TCPtrace RCV packet 25147 at  2-JAN-2014 13:01:34.41

 

                        IP Address       Port

 

   Source                10.51.3.18       809

   Destination           10.51.3.33        10

 

                                                Packet Length      120

   UDP

 

                                         Hex    Count   Ascii 

   --------   --------   --------   --------    ----    ----------------

   1203330A   DD20113F   00400000   78000045    0000    E..x..@.?. ..3..

   C1A5E935 | DA436400   0A002903 | 2103330A    0010    .3.!.)...dC.5...

   03000000   A5860100   02000000   00000000    0020    ................

   9D11C452   1C000000   01000000   01000000    0030    ............R...

   00000000   00002965   6E6F6E28   06000000    0040    ....(none)......

   00000000   00000000   00000000   00000000    0050    ................

   74737953   2F74726F   7078452F   13000000    0060    ..../Export/Syst

                         00617461   645F6D65    0070    em_data.       

 

--------------------------------------------------------------------------------

 

   TCPtrace XMT packet 25151 at  2-JAN-2014 13:01:34.41

 

                        IP Address       Port

 

   Source                10.51.3.35        10

   Destination           10.51.3.18       809

 

                                                Packet Length       96

   UDP

 

                                         Hex    Count   Ascii 

   --------   --------   --------   --------    ----    ----------------

   2303330A   06041180   0040ECDB   60000045    0000    E..`..@......3.#

   C1A5E935 | BD054C00   29030A00 | 1203330A    0010    .3.....).L..5...

   00000000   00000000   00000000   01000000    0020    ................

   53464E02   20000000   00000000   00000000    0030    ........... .NFS

   00040004   01280020   20202020   2030315F    0040    _10      .(.....

   00000000   882A4355   00000001   00170000    0050    ........UC*.....


The NFS request comes in 10.51.3.33 but is responded to on 10.51.3.35. At this point the client gives up. The problem is random (or seemingly random). The source and destination ports match up, the IP address don't. 

 

The requesting system is running a variant of linux.

 

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