PING command

Use the Ping IP Address dialog to invoke the z/OS Communications Server PING command and receive the output of that command.

The z/OS Communications Server PING command sends an echo request to a foreign node (remote host) to determine whether the node is accessible. When a response to a PING command is received, the elapsed time is displayed. The time does not include the time spent communicating between the user and the TCP/IP address space.

This dialog has two areas: a command input area where you specify the characteristics of the command you want to issue and the command output area where the results of the command are displayed.

Complete explanations of the fields in this dialog are found in the IBM z/OS Communications Server: Administrator's Commands book for your level of z/OS. Brief explanations of these fields follow.

The only required field is the Hostname or IP Address field and it is prefilled with IP address from the row or bar-graph bar from which you issued the take action command.

The remaining fields in this dialog box are prefilled with the default values when the dialog is initialized. You can change the value of any modifiable field before invoking the command. Field-level validation is performed before command execution. You are prompted by the dialog to correct invalid data.

Hostname or IP Address: Specifies the host to which you want to send the echo request. This must be an IP address or a host name that can be resolved. This may be an IPv4 address or an IPv6 address. IPv4-mapped IPv6 addresses are not supported. IPv4 addresses can take one of these formats:

d.d.d.d: When a four-part address is specified, each part is interpreted as a byte of data and is assigned, from left to right, to the four bytes of an IPv4 address.
d.d.d: When a three-part address is specified, the last part is interpreted as a 16-bit quantity and placed in the right-most two bytes of the network address. This format makes the three-part address format convenient for specifying Class B network addresses, such as 128.net.host.
d.d:When a two-part address is supplied, the last part is interpreted as a 24-bit quantity and placed in the right-most three bytes of the network address. This makes the two-part address format convenient for specifying Class A network addresses, such as net.host.
d: When only one part is given, the value is stored directly in the network address without any byte rearrangement

When using IPv6 link-local addresses, you can provide scope information with the IP address or host name. To specify scope information, add a percent character (%) after the Hostname or IP Address value, followed by the scope information (usually an interface name). The combined length of the Hostname or IP Address value and the scope information cannot exceed 255 characters.

For a more complete explanation about the use of scope information, see the support for scope information in the IBM z/OS Communications Server: IPv6 Network and Application Design Guide.

Source IP Address: Specifies the source IP address. You must specify this as an IP address and not a host name. IPv4-mapped IPv6 addresses are not supported. On hosts with more than one IP address, you can set the source address to the IP address for another one of the stack's interfaces. This can be a VIPA address. If the destination host is specified as a host name and the Addrtype option is not specified, the address type of the value is used to determine whether the host name should be resolved to an IPv4 or IPv6 IP address. For rules regarding the format of IPv4 and IPv6 addresses, see the Hostname or IP Address field in help.

Restriction: You cannot specify scope information for the source IP address.

Interface: Specifies the local interface, interface, over which the packets will be sent. The interface is either a maximum 16-byte name from a LINK or INTERFACE profile statement, or the IP address of a local interface. IPv4-mapped IPv6 addresses are not supported. Local VIPA or LOOPBACK interfaces are not valid.

Count: Sets the number of echo requests that are sent to the host. If you do not specify the count parameter, the default of 1 is used. The value must be in the range 1 to 10000.

Packet Size: Sets the number of data bytes for the echo request. If you do not specify the Packet Size, the default value 256 is used. The packet size must be in the range 8 - 65487 bytes. A minimum of 8 data bytes is needed for a time stamp value, which the PING command uses to correlate echo requests to echo replies.

Timeout: Sets the number of seconds that the PING command waits for a response. If you do not specify the a value for the timeout parameter, the default of 10 seconds is used. The number of seconds specified must be in the range 1 - 100.

NoName: Specifies that the PING command should not resolve IP addresses to host names for ICMP/ICMPv6 messages received due to Path MTU problems. This parameter is only in effect if the PTMU parameter was also specified, otherwise it is ignored. Specifying this parameter results in the PING command displaying only the IP address of the host where fragmentation is needed.

Verbose: Provides additional details about the received echo replies and a statistics summary.

If you do not specify the Verbose and Count parameters, then the default count of echo requests is 1.
If you specify the Verbose parameter without the Count parameter, then the default value is 3.
If you specify both the Verbose and Count parameters, then the number of echo requests is the value that is specified in the Count parameter.

TCP Stack: Specifies the name of the TCP/IP stack to be used. This field should be completed with the tcpname, the 8-byte procedure name that is used to start the TCP/IP.

Addrtype: Specifies the IP address type that the resolver used by the Tivoli Enterprise Portal should return when resolving the host name to an IP address. The values for this option are not case sensitive. Valid values are as follows:

IPv4 Specifies that only IPv4 IP addresses should be returned from the resolver used by the Tivoli Enterprise Portal when resolving the host name to an IP address.
IPv6 Specifies that only IPv6 IP addresses should be returned from the resolver used by the Tivoli Enterprise Portal when resolving the host name to an IP address.

If no Addrtype is specified, the dialog defaults to IPv4.

PMTU (Path Maximum Transmission Unit): This parameter can be used for diagnosing Path Maximum Transmission Unit (MTU) problems in the network. It prevents the outbound echo request packets from being fragmented and specifies what kind of Path MTU Discovery support should be used with the PING command. For IPv4, Path MTU Discovery support is enabled by specifying the PATHMTUDISCOVERY parameter on the IPCONFIG profile statement. For IPv6, Path MTU Discovery support is enabled by default. The values for this option are not case sensitive. Valid values are as follows:

Yes Specifies that the outbound echo request packets are not fragmented at the local host or in the network and that the MTU values, determined by path MTU discovery for the destination, are used.
Ignore: Specifies that the outbound echo request packets are not fragmented at the local host or in the network, and that any MTU values determined by path MTU discovery for the destination, are ignored.

When you have completed editing the fields in the Ping IP Address dialog, click OK to issue the specified PING command. Click Cancel to close the Ping IP Address dialog. Click Help to invoke the online help.