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IC97354: A DATAPOWER APPLIANCE'S DNS CONFIGURATION SET TO ROUND ROBIN DOES NOT HONOR THE TIME TO LIVE (TTL) SETTING

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APAR status

  • Closed as program error.

Error description

  • If the Load Balancing Algorithm in the DNS Settings is set to
    Round Robin, the TTL (time to live) setting might not be
    honored. The DNS resolution caches for lifetime.
    

Local fix

  • In the WebGUI, go to Network > Interface > DNS Settings and
    change the Load Balancing Algorithm from Round Robin, which is
    the default value, to First Alive.
    

Problem summary

  • Affected are all DataPower appliances that query DNS servers and
    obtain responses to AAAA query with OK response code, but no
    address records. This includes appliances with no IPv6
    networking configured. Only configurations using DNS
    with round-robin algorithm are affected.
    
    The appliance always sends out both A and AAAA DNS
    queries for every DNS name it does not hold in its cache.
    Depending on the mutual timing of the DNS responses to these
    queries, a DNS cache entry with invalid TTL value may be
    created. That invalid TTL may be long or virtually infinite.
    

Problem conclusion

Temporary fix

Comments

APAR Information

  • APAR number

    IC97354

  • Reported component name

    DTPWR INTGRAPL

  • Reported component ID

    DP905XI52

  • Reported release

    500

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-10-31

  • Closed date

    2013-12-18

  • Last modified date

    2014-01-22

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    DTPWR INTGRAPL

  • Fixed component ID

    DP905XI52

Applicable component levels

  • R500 PSN

       UP

  • R600 PSN

       UP

  • R601 PSN

       UP



Document information

More support for: WebSphere DataPower Integration Appliance XI52

Software version: 5.0.0

Reference #: IC97354

Modified date: 22 January 2014