Starting packet trace

To start packet trace, use the following command:

V TCPIP,tcpprocname,PKT

Security Note: To use any VARY command, the user must be authorized in RACF®.

The RACF profile for each user must have access for a resource of the form MVS™.VARY.TCPIP.xxx, where xxx is the first eight characters of the command name. For packet trace, this would be MVS.VARY.TCPIP.PKTTRACE.

Traces are placed in an internal buffer, which can then be written out using an external writer. The MVS TRACE command must also be issued for component SYSTCPDA to activate the packet trace.

After starting packet trace, you can display the status using the Netstat command, as shown in the following example:

NETSTAT -p TCPCS -d                                                  
MVS TCP/IP NETSTAT CS V1R10 TCPIP Name: TCPCS 18:03:31
DevName: LOOPBACK          DevType: LOOPBACK 
DevStatus: Ready  
LnkName: LOOPBACK          LnkType: LOOPBACK   LnkStatus: Ready    
  NetNum:  0   QueSize: 0   
  BytesIn: 192537                  BytesOut: 192537  
  ActMtu:  65535  
BSD Routing Parameters:  
  MTU Size: 00000             Metric: 00  
  DestAddr: 0.0.0.0           SubnetMask: 0.0.0.0  
Packet Trace Setting:  
  Protocol: *                 TrRecCnt: 00000000  PckLength: FULL  
  Discard :  0
  SrcPort:  *                 DestPort: *         PortNum *  
  IpAddr:   9.67.113.1        SubNet:   *  
Multicast Specific:  
  Multicast Capability: No

In this example, the packet length (PckLength) is FULL and TrRecCnt is the number of packets written for this device.

Note: If you are a TSO user, use the corresponding NETSTAT DEV command.