EZZ9308E

Explanation
 This message is issued when the resolver detects
that the specified name server failed to respond to a percentage of
resolver queries. The percentage of failed resolver queries is in
excess of the threshold that is specified by using the UNRESPONSIVETHRESHOLD
resolver setup statement. 
 In the message text:  ipaddress
The IPv4 or IPv6 network address of the name server that  is considered
unresponsive.

System action
 Processing continues. The resolver continues
to send queries to the name server  while the name server is specified
in the TCPIP.DATA data sets used by the  installation.   
 The
message remains on the operator console until one of the following
events  occurs:  During a future monitor checkpoint, the percentage of resolver
queries to which  the name server has failed to respond drops below
the UNRESPONSIVETHRESHOLD  percentage. 
You change the UNRESPONSIVETHRESHOLD value to zero by using the MODIFY
RESOLVER,REFRESH,SETUP=setup_file_name command.
Changing the value of the UNRESPONSIVETHRESHOLD 
parameter to zero disables the monitoring function, so no additional
EZZ9308E  messages will be generated until the function is re-enabled.

The resolver is stopped.

Operator response
 Contact the system programmer.

System programmer response
 Determine if the name server is unresponsive
due to a network condition, a  configuration error, or a temporary
condition that might resolve itself later.  If a network condition is preventing resolver requests or name
server responses  from reaching the correct destination, correct the
network condition. When  requests can successfully reach the name
server and are being responded to, the  resolver will detect the change
in responsiveness at the next monitor interval  and will clear the
message from the operator console.  
If a configuration error is causing the name server to be unresponsive,
use  resolver diagnostic tools such as MODIFY RESOLVER,DISPLAY or
Trace Resolver  output to determine which TCPIP.DATA data sets are
used in the failing resolver  queries and investigate the following
possibilities:   If the UNRESPONSIVETHRESHOLD value specifies a lower percentage
of errors than  your network can tolerate during typical operations,
increase the threshold  percentage in the resolver setup file. For
example, if the threshold percentage  is 25%, but your network can
tolerate 40%, increase the threshold to 40%-45%. 
If the IP address is no longer valid as a destination name server,
remove the  IP address from the list of name servers that were coded
by using the NSINTERADDR or NAMESERVER configuration statements. 
If the RESOLVERTIMEOUT value is coded so small that the response
is unable to  return from the name server within the specified time
value, increase the  timeout setting to a value that permits a larger
percentage of responses to  arrive within the timeout window.
When the configuration error is corrected, do one of the
following to cause the  resolver to use the updated configuration
information:  If you modified the setting of the UNRESPONSIVETHRESHOLD parameter,
have the  operator issue the MODIFY RESOLVER,REFRESH,SETUP=setup_file_name command. 
If you modified the  RESOLVERTIMEOUT parameter,
or if you removed an IP address from the list of name servers that
were coded with the NSINTERADDR or NAMESERVER  statement,  have the
operator  issue the MODIFY RESOLVER,REFRESH command.

If you eliminated a network condition and a configuration error
as the reason  for the message, then the resolver might be generating
the message for a  temporary condition that might resolve itself.
For example, the name server  might be having maintenance applied,
or the name server might have a very high  percentage of failures
because there were few queries sent to the name server  during the
monitoring interval, so even a short network interruption would  severely
impact the calculations. If this situation repeats itself, an overly
 aggressive UNRESPONSIVETHRESHOLD value might be contributing to the
situation.  Consider increasing the setting for the UNRESPONSIVETHRESHOLD parameter
in the  resolver setup file, and then have the operator issue the MODIFY
 RESOLVER,REFRESH,SETUP=setup_file_name command
to make the resolver less  sensitive to name server response failures.

User response
 Not applicable.

Problem determination
 Not applicable.

Source
 z/OS® Communications
Server TCP/IP: System Resolver

Module

Routing code
 2,8

Descriptor code
 12

Automation
 This message is a good candidate for automation.
Automation can alert the network operator to the condition, or it
can trigger processing to collect diagnostics, or it can monitor future
statistics related to the name server.

Example
  EZZ9308E UNRESPONSIVE NAME SERVER DETECTED AT IP ADDRESS 10.45.23.200