IT09309: DATAPOWER APPLIANCE SHOWS HIGH LATENCY IN DNS RESOLUTION

Fix packs for DataPower Gateway version 7.2

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 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