You can refresh the resolver address space from the operator console using the MODIFY command. Issue the REFRESH command to refresh the resolver address space and the DISPLAY command to display the current values of the resolver setup statements. Issue the FLUSH command to delete the contents of the resolver cache. You can also reset the current z/OS® knowledge of name server capabilities by issuing the REFRESH command.
For a description of the resolver setup statements, see Resolver setup statements in z/OS Communications Server: IP Configuration Reference.
>>-+-MODIFY-+--procname--,--------------------------------------> '-F------' >--+--------------------------------------+-------------------->< +-Display------------------------------+ +-REFRESH--+-------------------------+-+ | '-,--SETUP=--+-xxx------+-' | | +-xxx(yyy)-+ | | '-'/xxx'---' | '-FLUSH----,ALL------------------------'
RESOLVER PROC = DEFAULT
If DEFAULT is
displayed, then the procname value is RESOLVER.
Any other value must be used as the procname.Resets information about name server capabilities that was dynamically acquired. For example, a name server has been upgraded to support extension mechanisms for DNS (EDNS0). Issue the REFRESH command to reset the current information about the capability of the name server, forcing the z/OS resolver to dynamically determine the new capability.
Clears message EZD2037E from the network operator console. Issue the REFRESH command to restart the resolver unresponsive name server monitoring functions after the resolver had stopped them as a result of a system error.
Restriction: The REFRESH command resets information about all name servers.
The z/OS resolver uses EDNS0 to accept DNS UDP messages that have a length greater than 512 bytes when the name server also supports EDNS0. Using the less costly UDP protocol, EDNS0 results in improved DNS and resolver performance. See the information about Extension Mechanisms for DNS standards and the resolver in z/OS Communications Server: IP Configuration Guide for more details.
In some cases, the resolver statistics regarding name server responsiveness for all name servers are affected by a REFRESH command. This situation occurs when the REFRESH command is used to stop the name server monitoring functions or when the REFRESH command is used to switch between the autonomic quiescing of unresponsive name server function and the network operator notification function. In these situations, the resolver statistics are set to the value of 0 and the current unresponsive name server notification messages EZZ9308E or EZZ9311E are cleared from the operator console. If the REFRESH command does not result in any changes to the unresponsive name server monitoring function, the resolver statistics are not affected and the current unresponsive name server notification messages remain on the operator console. For information about when the statistics and messages are affected, see UNRESPONSIVETHRESHOLD statement in z/OS Communications Server: IP Configuration Reference.
If the REFRESH command is used to change the NSINTERADDR statement values coded in the TCPIP.DATA file specified on the GLOBALTCPIPDATA resolver setup statement, the resolver statistics regarding name server responsiveness for a single name server might be affected. If the REFRESH command is used to remove an unresponsive name server from the NSINTERADDR statements, the resolver will zero the resolver statistics for this name server, will stop sending resolver DNS polling queries to the name server, and will clear the EZZ9311E unresponsive name server notification message from the operator console. For information on the NSINTERADDR statement, see NSINTERADDR statement in z/OS Communications Server: IP Configuration Reference.
f resolver,display
EZZ9298I DEFAULTTCPIPDATA - None
EZZ9298I GLOBALTCPIPDATA - SYS1.TCPPARMS(TCPDATA)
EZZ9298I DEFAULTIPNODES - USER55.ETC.IPNODES
EZZ9298I GLOBALIPNODES - None
EZZ9304I NOCOMMONSEARCH
EZZ9304I CACHE
EZZ9298I CACHESIZE - 200M
EZZ9298I MAXTTL - 2147483647
EZZ9298I UNRESPONSIVETHRESHOLD - 25
EZZ9293I DISPLAY COMMAND PROCESSED
f resolver,display
EZZ9298I DEFAULTTCPIPDATA - None
EZZ9298I GLOBALTCPIPDATA - SYS1.TCPPARMS(TCPDATA)
EZZ9298I DEFAULTIPNODES - USER55.ETC.IPNODES
EZZ9298I GLOBALIPNODES - None
EZZ9304I NOCOMMONSEARCH
EZZ9304I CACHE
EZZ9298I CACHESIZE - 200M
EZZ9298I MAXTTL - 2147483647
EZZ9298I UNRESPONSIVETHRESHOLD – 25
EZD2039I WARNINGS ISSUED DURING RESOLVER INITIALIZATION
EZZ9293I DISPLAY COMMAND PROCESSED
f resolver,display
EZZ9298I DEFAULTTCPIPDATA - None
EZZ9298I GLOBALTCPIPDATA - SYS1.TCPPARMS(TCPDATA)
EZZ9298I DEFAULTIPNODES - USER55.ETC.IPNODES
EZZ9298I GLOBALIPNODES - None
EZZ9304I NOCOMMONSEARCH
EZZ9304I CACHE
EZZ9298I CACHESIZE - 200M
EZZ9298I MAXTTL - 2147483647
EZZ9298I UNRESPONSIVETHRESHOLD - 25
EZZ9304I AUTOQUIESCE
EZD2305I NAME SERVER 10.1.1.1
STATUS: ACTIVE FAILURE RATE: 0%
EZD2305I NAME SERVER 10.2.2.2
STATUS: QUIESCED FAILURE RATE: 60%
EZD2305I NAME SERVER 10.3.3.3
STATUS: ACTIVE FAILURE RATE: *NA*
EZZ9293I DISPLAY COMMAND PROCESSED
The following example shows how to change some of current values in user55.ressetup setup file, such as changing NOCOMMONSEARCH to be COMMONSEARCH and changing the file name of DEFAULTIPNODES to be USER1.ETC.IPNODES.
f resolver,refresh,setup=user55.ressetup
EZZ9298I DEFAULTTCPIPDATA - None
EZZ9298I GLOBALTCPIPDATA - SYS1.TCPPARMS(TCPDATA)
EZZ9298I DEFAULTIPNODES - USER1.ETC.IPNODES
EZZ9298I GLOBALIPNODES - None
EZZ9304I COMMONSEARCH
EZZ9304I CACHE
EZZ9298I CACHESIZE - 200M
EZZ9298I MAXTTL - 2147483647
EZZ9298I UNRESPONSIVETHRESHOLD - 25
EZZ9293I REFRESH COMMAND PROCESSED
f resolver,flush,all
EZZ9305I 200 CACHE ENTRIES DELETED
EZZ9293I FLUSH COMMAND PROCESSED
See the resolver setup statements in the resolver setup file topic in z/OS Communications Server: IP Configuration Guide for an explanation of the fields on the report.