Managing multiple network interfaces

Edit online

If you have multiple network interfaces, you can set the priority of the interfaces to use by using interface lists.

If your site runs more than one TCP/IP interface or network adapter on the same z/OS® image, you can specify network interfaces to be used by monitoring servers and monitoring agents on a z/OS system.

You specify the network interfaces in the IP communication protocol parameters for each component.

When you have multiple network interfaces, you manage their priority of use through a set of configuration and embed parameters named *_KDEB_INTERFACELIST and KDEB_INTERFACELIST*, respectively.

The configuration process is different for IPv4 and IPv6 communication.

Configuration parameters (for IPv4 only)

The following configuration parameters are available for setting the network interface to use for IPv4 communication.
Note: For setting the network interface to use for IPv6 communication, you must use embed override variable KDEB_INTERFACELIST_IPV6, which is described later in this topic.
Important: If you need to update the following parameter values, use Configuration Manager or PARMGEN to modify your configuration.
RTE_TCP_KDEB_INTERFACELIST (valid in Configuration Manager only)
This Configuration Manager-only parameter directs all components in the runtime environment to connect to a specific TCP/IP local interface for IPv4 communication.

This parameter sets the value of parameters KDS_TEMS_TCP_KDEB_INTERFACELIST (for the monitoring server) and Kpp_AGT_TCP_KDEB_INTERFACELIST (for the monitoring agents).

If you want to disable all network interfaces for IPv4 in the runtime environment (for example, if you are moving from IPv4 to IPv6), perform the following steps:
  1. If defined, remove parameters KDS_TEMS_TCP_KDEB_INTERFACELIST and Kpp_AGT_TCP_KDEB_INTERFACELIST from members RTEDEF(Kpp$PARM) and RTEDEF(Kpp$lpar).
  2. In RTEDEF(rte_name), set the following parameter and value:
    RTE_TCP_KDEB_INTERFACELIST "-"
KDS_TEMS_TCP_KDEB_INTERFACELIST
This parameter specifies a list of network interfaces for the monitoring server to use for IPv4 communication.
For Configuration Manager:
You can use this parameter to set the list of network interfaces for the monitoring server to use for IPv4 communication, or you can use parameter RTE_TCP_KDEB_INTERFACELIST, which sets the value for all components in the runtime environment.
For PARMGEN:
This parameter is required to use IPv4 communication.
To disable the network interfaces for IPv4 for the monitoring server, set the value as follows:
KDS_TEMS_TCP_KDEB_INTERFACELIST "-"
Kpp_AGT_TCP_KDEB_INTERFACELIST
This parameter specifies a list of network interfaces for the monitoring agent to use for IPv4 communication.
For Configuration Manager:
You can use this parameter to set the list of network interfaces for the monitoring agent to use for IPv4 communication, or you can use parameter RTE_TCP_KDEB_INTERFACELIST, which sets the value for all components in the runtime environment..
For PARMGEN:
This parameter is required to use IPv4 communication.
To disable the network interfaces for IPv4 for the monitoring agent, set the value as follows:
Kpp_AGT_TCP_KDEB_INTERFACELIST "-"

Embed override parameters (environment variables)

The following embed override parameters (environment variables) indicate the network interface to use depending on IPv4 or IPv6 communication:

KDEB_INTERFACELIST (for IPv4 only)

Contains a list of interface addresses in the order for which these interface addresses should be discovered and used for IPv4 communication.

To update this setting, you use the configuration parameters, as follows:
  • Using Configuration Manager, modify the RTE_TCP_KDEB_INTERFACELIST parameter value.
  • Using PARMGEN, modify the KDS_TEMS_TCP_KDEB_INTERFACELIST and Kpp_AGT_TCP_KDEB_INTERFACELIST parameter values.
If you are using IPv6, this parameter must be set as follows:
KDEB_INTERFACELIST='-'
KDEB_INTERFACELIST_IPV6 (for IPv6 only)

Contains a list of interface addresses in the order for which these interface addresses should be discovered and used for IPv6 communication.

By default, this parameter is commented out:
*KDEB_INTERFACELIST_IPV6=-
To update the parameter, remove the asterisk (*) and replace the hyphen (-) with one or more interface addresses.
Numeric IPv6 addresses must be enclosed in parentheses. Multiple addresses are separated by a backslash (\). For example:
KDEB_INTERFACELIST_IPV6=\
(2002:930:9b04:305:9:48:133:98)\
(2002:930:9b04:305:9:48:133:100)
To update this setting::

Information required for network interface list

When configuring the network interface list for the monitoring server, you need the following information:

  • The host name or IP address of the preferred interface.
  • A list of host names or IP addresses, in descending order of preference. Use a blank (space) to separate the entries.
  • An asterisk (*) to prefer the interface associated with the default host name for the z/OS image. To display this value, enter TSO HOMETEST at the command-line.
  • An exclamation point followed by an asterisk (!*) to use only the interface associated with the default host name for the z/OS image.
  • An exclamation point followed by a host name or IP address (!hostname) to use only the interface associated with hostname.
    Note: A high-availability hub uses a dynamic virtual IP address (DVIPA).
  • A minus sign followed by a host name or IP address (-hostname) to use any interface except the one associated with hostname.
Note:
  • If you set the value of this parameter to !* or !hostname, you must specify the same value for every component and product configured in all runtime environments on the same z/OS image.
  • In the default character set (LANG=en_US.ibm-037), the code for an exclamation point is x'5A'. If you are using a character set other than the default, a different character might map to that code. To require a specific network interface, use the character that maps to x'5A' in your character set.

Related links