WebSphere MQ Channels waiting on Domain Name Server
Rick_Armstrong 20000064V1 Comments (2) Visits (11053)
We see the problem mentioned in the title "WebSphere MQ Channels waiting on Domain Name Server" quite often in Websphere MQ Level 2 Support. It manifests itself in a variety of ways:
In order to fix the problem we need to understand the problem. When a channel connection request is made. The CHINIT will do a TCPIP Resolver call, getnameinfo(), to resolve the IP address coming in to a hostname. This is done to provide more meaningful information in channel messages (i.e hostname instead of an IP address). This can happen when a channel is stopping as well. If the TCPIP Resolver call is delayed you can experience this problem.
Why would the TCPIP Resolver call be delayed you ask! We usually find two reasons
To investigate further requires TCPIP knowledge and traces. From a z/OS perspective please refer to the technote entitled Using the Resolver CTRACE when conventional traces do not work. The Resolver trace output will identify which of the two points above is the culprit or of there is another problem.
For further information from WebSphere MQ regarding this problem please refer to the technote entitled WebSphere MQ channel status has SUBSTATE = NAMESERVER.