Requirements: To enable AF_INET6 support in a Common INET environment, the following conditions must exist:

• AF_INET6 must be configured in BPXPRMxx. AF_INET6 support can be dynamically enabled by configuring AF_INET6 in BPXPRMxx and then issuing the SETOMVS RESET= command to activate the new configuration.
• At least one dual-mode-capable stack must be started after AF_INET6 is configured in BPXPRMxx. Note that any dual-mode capable TCP/IP stack started before configuring BPXPRMxx remains an IPv4-only stack as long as it remains active. However, if it is stopped and then restarted, it restarts as a dual-mode TCP/IP stack if AF_INET6 is configured in BPXPRMxx at the time it is restarted.

Guideline: Do not start some z/OS® Communications Server TCP/IP stacks with AF_INET6 support and some without AF_INET6 support. If AF_INET6 support is dynamically enabled, you should stop and restart all TCP/IP stacks which were active when AF_INET6 support was enabled. This allows these TCP/IP stacks to become dual-mode stacks. After this occurs, all applications which are capable of opening AF_INET6 sockets should be stopped and restarted. This allows the restarted applications to communicate over IPv4 and IPv6 networks.