Technote (FAQ)
Question
Once I have PATHMTU running correctly is there some sort of display that I can see showing what it discovered for my EE connection? I guess I am looking for some sort of display similar to a trace route showing the path it took and the MTU it discovered along the way to make its adjustments.
Answer
See the information here on using the PING command to display MTU: the section "Determine the path MTU size to a host" in topic 1.4.7.1 "Using the Ping Command" of the z/OS Communications Server IP Diagnosis book.
Here is an example of using the TSO PING command with PMTU yes.
Here is an example of using the z/OS UNIX ping command with -P yes.
In the "Determining the maximum transmission unit" section of the IP Configuration Guide, there is this statement: "For an active link or interface, TCP/IP reports the interface MTU value in the ActMtu field of the Netstat DEVLINKS/-d report."
The syntax of the command to be used is :
D TCPIP,tcpprocname,NETSTAT,DEV
The above command will show characteristics of all interfaces in the display produced.
To limit the display to a single interface, use this command:
DISPLAY TCPIP,tcpprocname,NETSTAT,DEV,INTFN=interface_name
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