Use the following option to control sending of unicast packets:

IPV6_UNICAST_HOPS

The IPv6 header contains a hop limit field that controls the number of hops over which a datagram can be sent before being discarded. This is similar to the TTL field in the IPv4 header. The IPV6_UNICAST_HOPS socket option can be used to set the default hop limit value for an outgoing unicast packet. The socket option value should be between 0 and 255 inclusive. A socket option value of -1 is used to clear the socket option. This causes the stack default to be used.

A getsockopt() with this option returns the value set by a setsockopt(). If a setsockopt() has not been performed, the stack's default value is returned.

The HOPLIMIT parameter on the IPCONFIG6 statement influences the default hop limit when this socket option is not set. An application must be APF-authorized or have superuser authority to set this option to a value greater than the value of HOPLIMIT on the IPCONFIG6 statement. See z/OS Communications Server: IP Configuration Guide for more information about the IPCONFIG6 statement.

Tip: This function is similar to the IPv4 socket option IP_TTL.