[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference lassie::ucx

Title:DEC TCP/IP Services for OpenVMS
Notice:Note 2-SSB Kits, 3-FT Kits, 4-Patch Info, 7-QAR System
Moderator:ucxaxp.ucx.lkg.dec.com::TIBBERT
Created:Thu Nov 17 1994
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:5568
Total number of notes:21492

5214.0. "proxies and multihomed hosts" by UTRTSC::KNOPPERS (Oswald Knoppers) Tue Feb 11 1997 03:23

Hello,

Question about communication proxies. My customer has a multihomed host
define in DNS/BIND. Something like:

ahatje                          in a 123.123.123.123
                                in a 23.23.23.23

On another system he adds the following proxy:

UCX> add prox knoppers/remote=aha/host=ahatje

The remote host (ahatje) is not in the locat host file. Now when you give
'show proxy' commands you see the following:

UCX> sho prox

VMS User_name     Type      User_ID    Group_ID   Host_name

KNOPPERS          C      AHA                      AHATJE
UCX> sho prox

VMS User_name     Type      User_ID    Group_ID   Host_name

KNOPPERS          CD     AHA                      AHATJE
UCX> sho prox

VMS User_name     Type      User_ID    Group_ID   Host_name

KNOPPERS          C      AHA                      AHATJE
UCX>
[etc]

I.e. the proxy only works half of the time. As far as I can see the only
workaround is to add the proxy as two proxies, for instance with the two IP
addresses. 

Is this intended? Should the 'add proxy' command not add proxies for all
addresses returned by the name lookup?

Thanks,

Oswald
T.RTitleUserPersonal
Name
DateLines
5214.1DNS load balancing ?BACHUS::ROELANDTSWa d'es ma da ve ne stuutTue Feb 11 1997 06:2710
    
    Oswald,
    
    What shows up when you do in UCX a : show host/nolocal ahatje ? Do you
    get alternatively the 1st then the 2d IP-address ? Could it be that the
    system is using the Round Robin DNS load balancing ?
    
    Rgds
    
         Guy
5214.2yes, dns does do round robinUTRTSC::KNOPPERSOswald KnoppersTue Feb 11 1997 09:3313
Yes, sorry I forgot to include that info. Yes the server is doing round
robin and obviously this is the source of the problem.

Apparently when you create the proxy, the dns server is queried, and the
first returned address is actually used in the proxy. Then each time a 
'show proxy' again queries the server and half of the times the same
address is returned first.

Any thoughts?

Regards,

Oswald
5214.3do you need it ?BACHUS::ROELANDTSWa d'es ma da ve ne stuutTue Feb 11 1997 10:0715
    
    
    Oswald,
    
    Do you need the Round Robin functionality ? Otherwise there is a
    logical that you can define to stop it : it is the logical 
    
    UCX$BIND_ROUND_ROBIN_OFF
    
    Note 5145 in this conference talks a bit about it.
    
    Rgds,
    
         Guy
    
5214.4a bug is an undocumented feature :-)UTRTSC::KNOPPERSOswald KnoppersTue Feb 11 1997 10:148
I don't think in this case the server is UCX based. Current workaround is
to add two proxies for the two different IP addresses. Obviously not very
elegant. Therefore this question. Is this behaviour a) expected b) bug or 
c) limitation...

Thanks,

Oswald