In most cases, no configuration in Ingres is required to implement IPv6 support. It is automatically enabled in the tcp_ip network protocol starting with Ingres 9.1.

The tcp_ip protocol driver also continues to support IPv4 addresses without any configuration changes needed; the driver will detect and process IPv4 addresses, IPv6 addresses, and both, if present concurrently.

Some versions of operating systems, however, provide no or limited support for IPv6. In some cases, IPv6 support is available, but must be enabled or configured in the operating system before it can be used. On systems with partial or no IPv6 functionality, Ingres will adjust automatically to the level of IPv6 support available. On some systems, however, Ingres may have difficulty, particularly when starting up or establishing connections.

For those rare situations, configuration parameters can be used to "back out" the IPv6 support, if required, or to restrict TCP support to IPv6 addresses only. These parameters (see Parameters for Controlling IPv6 Support), which are not available in the configuration utilities, must be set with set, ingsetenv, or iisetres commands.

On Windows, the iicvtwintcp utility (see iicvtwintcp Command--Convert wintcp to tcp_ip Protocol Setting) can be used to convert wintcp settings to tcp_ip settings, or to subsequently restore the settings to their previous values.