IC86912: DATAPOWER DOES NOT USE THE TTL VALUE PASSED IN THE DNS CNAME RECORD.

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Datapower only uses the Time To Live (TTL) value in the DNS A
    Record. The appliance
    should also consider the TTL value passed in the CNAME
    field, and use this value if it is shorter than the TTL value of
    the A Record
    

Local fix

Problem summary

  • Affected are customers using the Datapower appliance to
    reference other network devices via DNS aliases in an
    environment where these DNS aliases might change.
    
    When resolving a DNS alias name where the timeout associated
    with the alias to a canonical name is shorter than the one
    associated with the canonical name's IP address, Datapower was
    failing to re-resolve the alias name immediately after its DNS
    record had expired.
    
    Datapower DNS resolution component honors only the TTL value
    returned in A or AAAA DNS records, failing to account for
    the TTL
    value in CNAME records. Therefore, if a network alias name were
    resolved via a pair of DNS records, e.g. of CNAME and A types,
    and the TTL value of CNAME record were shorter than the one of
    the
    A record, Datapower would cache the name-to-address translation
    entry using the A TTL, effectively disregarding the CNAME TTL
    value, which is not compliant with RFC-1034.
    

Problem conclusion

Temporary fix

  • Customers that have control over their DNS infrastructure can
    configure the server to use timeout values on their A or AAAA
    records to be shorter than the ones for CNAME records.
    

Comments

APAR Information

  • APAR number

    IC86912

  • Reported component name

    DATAPOWER

  • Reported component ID

    DP1234567

  • Reported release

    401

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-10-01

  • Closed date

    2012-11-13

  • Last modified date

    2012-11-23

  • 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

    DATAPOWER

  • Fixed component ID

    DP1234567

Applicable component levels

  • R382 PSN

       UP

  • R401 PSN

       UP

  • R402 PSN

       UP

  • R500 PSN

       UP



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Document information


More support for:

IBM DataPower Gateways
General

Software version:

4.0.1

Reference #:

IC86912

Modified date:

2012-11-23

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