The IPCONFIG statement group can be used to control characteristics related to the IP layer function of the TCP/IP stack. Some of these parameters are related to sysplex functioning.

Of note in the IPCONFIG group are controls for datagram forwarding. Forwarding is the act of moving a datagram between two different networks or subnetworks. TCP/IP can be configured to not allow any datagrams to be forwarded. This prevents TCP/IP from inadvertently being used as a router. The option controlling this is the DATAGRAMFWD option.

TCP/IP on z/OS is usually a multi-homed host. In other words, it has more than one IP address (link) associated with it. Quite often, it has at least one OSA-Express card connecting it to the network, with one or more specialized links connecting it to other hosts. If the links are redundant (that is, the routes to each link have equal costs), the IP layer can be configured to utilize all routes of equal cost. The option controlling this is the MULTIPATH option.