Communications Server for z/OS V1R7 TCP/IP Implementation, Volume 1: Base Functions, Connectivity, and Routing

Chapter 4. Connectivity 135

IST1802I P4 CURRENT = 0 AVERAGE = 0 MAXIMUM = 0

IST1221I DATA DEV = EB03 STATUS = ACTIVE STATE = N/A

IST1724I I/O TRACE = OFF TRACE LENGTH = *NA*

The DYNAMICXCF configuration created a SAMEHOST TRLE named IUTSAMEH. The

related TRLE status can be displayed, as shown in Example 4-23.

Example 4-23 D NET,TRL,TRLE=IUTSAMEH

D NET,TRL,TRLE=IUTSAMEH

IST097I DISPLAY ACCEPTED

IST075I NAME = IUTSAMEH, TYPE = TRLE 491

IST1954I TRL MAJOR NODE = ISTTRL

IST486I STATUS= ACTIV, DESIRED STATE= ACTIV

IST087I TYPE = LEASED , CONTROL = MPC , HPDT = YES

IST1715I MPCLEVEL = HPDT MPCUSAGE = SHARE

IST1717I ULPID = TCPIPA

IST314I END

4.4.6 Problem determination

Isolating network problems is an essential step to verify a connectivity problem in your

environment. This section introduces commands and techniques that can use to diagnose

network connectivity problems related to a specific interface.

The following diagnostic commands are available for either the z/OS UNIX environment or

the TSO environment:

򐂰 PING - The PING command can be very useful to determine if a destination address can

be reached in the network. Based on the results, it is possible to define whether the

problem is related to the interface being tested, or whether it is a network-related problem.

Using PING we can verify the following:

򐂰 The directly attached network is defined correctly.

򐂰 The device is properly connected to the network.

򐂰 The device is able to send and receive packets on the network.

򐂰 The remote host is able to receive and send packets.

When a PING command is issued, you can receive any of the responses listed in Table 4-4.

Table 4-4 Using PING command as a debugging tool

PING command (direct

network)

PING response Possible cause and actions

ping 10.10.2.1 (intf

osa2080lnk

C S V 1 R 7 : P i n g i n g h o s t 1 0 . 1 0 . 2 . 1

sendMessage(): EDC8130I Host

cannot be reached.

The interface being tested has

a problem. Use the Netstat

command to verify the interface

status.

ping 10.10.2.1 (intf

osa2080lnk

CS V1R7: Pinging host 10.10.2.1

Ping #1 timed out

It means the ICMP packet has

been sent to the network, but

the destination address is either

invalid or it is not able to answer.

Correct the destination address

or verify the destination host

status. This problem should be

verified in the network.

136 Communications Server for z/OS V1R7 TCP/IP Implementation, Volume 1 - Base Functions, Connectivity, and Routing

򐂰 Netstat - We can use the Netstat command to verify our TCP/IP configuration. The

information provided in the output from the Netstat command should be checked against

the values in our configuration data sets for the TCP/IP stack. To verify our connectivity

status from an interface perspective, we can use the following Netstat options:

– Netstat HOME/-h shows all defined interfaces and their IP addresses, even those

interfaces dynamically created, as shown in Example 4-24.

Example 4-24 NETSTAT HOME command results

D TCPIP,TCPIPA,N,HOME

EZD0101I NETSTAT CS V1R7 TCPIPA 109

HOME ADDRESS LIST:

LINKNAME: STAVIPA1LNK

ADDRESS: 10.10.1.230

FLAGS: PRIMARY

LINKNAME: OSA2080LNK

ADDRESS: 10.10.2.232

FLAGS:

LINKNAME: IUTIQDF4LNK

ADDRESS: 10.10.4.234

FLAGS:

LINKNAME: EZASAMEMVS

ADDRESS: 10.20.10.100

FLAGS:

LINKNAME: IQDIOLNK0A140A64

ADDRESS: 10.20.10.100

FLAGS:

LINKNAME: LOOPBACK

ADDRESS: 127.0.0.1

FLAGS:

INTFNAME: LOOPBACK6

ADDRESS: ::1

TYPE: LOOPBACK

FLAGS:

12 OF 12 RECORDS DISPLAYED

– Netstat DEVLINKS/-d shows the status of each interface, physical and logical, defined

in the TCP/IP stack, as shown in Example 4-25 (only one interface shown as an

example).

Example 4-25 NETSTAT DEVLINKS command results

DISPLAY TCPIP,TCPIPA,N,DEV,INTFN=OSA2080LNK

EZD0101I NETSTAT CS V1R7 TCPIPA 180

DEVNAME: OSA2080 DEVTYPE: MPCIPA

DEVSTATUS: NOT ACTIVE

LNKNAME: OSA2080LNK LNKTYPE: IPAQENET LNKSTATUS: NOT ACTIVE

NETNUM: N/A QUESIZE: N/A

IPBROADCASTCAPABILITY: NO

CFGROUTER: NON ACTROUTER: UNKNOWN

ACTMTU: UNKNOWN

SECCLASS: 255

BSD ROUTING PARAMETERS:

ping 10.10.2.1 (intf

osa2080lnk

CS V1R7: Pinging host 10.10.2.1

Ping #1 response took 0.000

seconds.

This is the expected response.

The interface is working.

PING command (direct

network)

PING response Possible cause and actions