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IT09309: DATAPOWER APPLIANCE SHOWS HIGH LATENCY IN DNS RESOLUTION

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • The DataPower appliance shows higher than expected latency
    connecting to IPv4 addresses resolved via DNS that might
    be caused by slow IPv6 DNS server responses.
    

Local fix

Problem summary

  • Affected are Datapower configurations using DNS resolution in
    environments where responses to IPv6 address (AAAA) queries have
    higher latency than responses to IPv4 address (A) queries. This
    is a common situation in many corporate networks that do not use
    IPv6.
    
    Datapower queries both A and AAAA DNS records whenever it is
    resolving a DNS name, waiting for both responses to come
    back (or time out). Thus the latency of a DNS query from
    Datapower is determined by the slower of both responses,
    regardless of the actual need for IPv6 address.
    
    The fix introduces a new control in DNS settings: "Force IP
    Preference", that can be used to restrict the DNS query to the
    preferred address family, avoiding the latency of querying the
    alternate address. By default, the feature is off to preserve
    compatibility with earlier releases.
    

Problem conclusion

  • The fix is available in 7.2.0.0.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT09309

  • Reported component name

    DATAPOWER

  • Reported component ID

    DP1234567

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2015-06-08

  • Closed date

    2015-06-19

  • Last modified date

    2015-06-19

  • 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

  • R720 PSN

       UP



Document information

More support for: IBM DataPower Gateways
General

Software version: 6.0.0

Reference #: IT09309

Modified date: 19 June 2015