Db2 for z/OS & Db2ZAI

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  • 1.  GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Thu December 05, 2024 09:40 AM

    Helo every DB2 Gurus!

    In my z/OS system log I found 1000 and 1000 messages in the following form:

    DSNL512I  - DSNLILNR TCP/IP 877                  
    GETHOSTBYADDR(192.168.200.1) FAILED WITH         
               RETURN CODE=1 AND REASON CODE=00000000 

    This message appeared every 3 seconds. Which manner Can I stop this?

    Best Regards

    Győző



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    Gyozo Karsai
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  • 2.  RE: GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Fri December 06, 2024 02:06 AM
    Edited by Manoj Jadwani Fri December 06, 2024 02:06 AM

    Hello ,

    Usually these type of messages are seen on DR site when Db2 failover happens and DNS entries and TCP profile are still being stabilized , usually network and z/OS sys progs can help you to figure out the problem.
    If this is your production system work with network and z/OS team and enquire if there were any recent changes .

    STOP DDF should stop the messages being logged to MSTR but you do not want to do that as it will stop DBAT connections to this Db2.

    Found this APAR which describes what actions one can take to diagnose.

    https://www.ibm.com/support/pages/apar/II10962 

    Hope this helps.

    Regards,
    Manoj K Jadwani



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    Manoj Jadwani
    Product Manager
    BMC Software
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    Original Message


  • 3.  RE: GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Fri December 06, 2024 02:26 AM

    Very odd - I get this one:

    DSNL512I  -xxxx DSNLILNR TCP/IP DVIPA 970        
    ACTIVATION(::192.1nn.n.nn) FAILED WITH            
               RETURN CODE=121 AND REASON CODE=766C7303

    but every three minutes and only from one subsystem...

    I do not let it worry me...as it is non-prod



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    Roy Boxwell
    Senior Software Architect
    Software Engineering GmbH
    Duesseldorf
    +4921196149675
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    Original Message


  • 4.  RE: GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Fri December 06, 2024 03:58 AM

    Hi Győző,

    I've come across this occasionally in the past, and solved it by editing etc/hosts to include the IP address/hostname of your z/OS system.

    Hope this helps.

    Regards,

    Gary Maltby



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    GARY MALTBY
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    Original Message


  • 5.  RE: GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Fri December 06, 2024 04:05 AM
    Edited by Diego Cardalliaguet Fri December 06, 2024 05:08 AM

    Hi there, 

    the return code 1 means that there's no domain available, as you can see here:

    USS Return codes

    How Db2 aquires IP and domain is explained here, first paragraph:

    https://www.ibm.com/docs/en/db2-for-zos/12?topic=messages-dsnl512i

    A gethostbyaddr() call is expecting a domain in return. The ip given by Db2 is probably correct. The problem is that a wrong, or no domain, is given to this call. And the return code is very clear: no domain available.

    The most probable cause is that the resolver is not working well. You should look at the TCP.PROFILE and/or the USS configuration. 

    Hope it helps.



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    Diego Cardalliaguet
    IBM Data&AI zStack Leader for EMEA
    IBM
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    Original Message


  • 6.  RE: GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Fri December 06, 2024 04:44 AM

    What IP address do you have in your BSDS? 

    Is that IP address valid for you z/OS system?

    See more info & instructions here https://www.ibm.com/support/pages/apar/II14515



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    Jørn Thyssen
    Principal Solutions Advisor
    Rocket Software
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    Original Message


  • 7.  RE: GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Fri December 06, 2024 02:29 PM

    Hey

    GETHOSTBYADDR is issued by DDF during startup(unitl V8 I guess. startup process changed in V9 because of IPV6 support). 
    If you see DSNL512I, I think your site is missing definitions in TCP/IP for DDF.
    You'll needs to resolve host name from IP address shown, meaning refering proper DNS or add definitions to local resolver( /etc/hosts, TCPIP.HOSTS.LOCAL, etc, whatever your site uses).



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    Yasuhiro Ohmori
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    Original Message


  • 8.  RE: GETHOSTBYADDR(192.168.200.1) FAILED

    Posted Fri December 06, 2024 04:21 PM

    1) If the z/OS has a /etc/hosts file ..... eliminate it .... it will result in symptom reported

    2) Check content of TCPIP.HOSTS.LOCAL .... if inaccurate, then correct and tso makesite hlq=TCPIP



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    Paul Newton
    Consulting IT Specialist
    IBM
    Coppell
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    Original Message