z/OS V2R1 is the last release which will support the GATEWAY statement. To migrate your static routing definitions to the BEGINROUTES block, try this tip: Take a dump of your TCP/IP stack. Use IPCS against the dump and issue the command TCPIPCS PROFILE(CONVERT). The resulting output will represent your GATEWAY definitions in BEGINROUTES format. You can then review this output to assist in modifying your TCP/IP profile. For more details on TCPIPCS PROFILE(CONVERT), see the IP Diagnosis Guide.