Choosing which form of dynamic VIPA support to use

The following list explains which of the features to use for the type of application that is being used.

• When to use VIPADEFINE and VIPABACKUP to define a dynamic VIPA:
  • One or more applications bind to the IPv4 INADDR_ANY address or to the IPv6 unspecified address (in6addr_any), and the applications exist on multiple TCP/IP stacks.
  • Dynamic VIPA takeover is wanted.
  • The DVIPA does not need to be deleted when the application is stopped.
• When to use VIPARANGE and bind() to define a dynamic VIPA:
  • The application cannot bind to INADDR_ANY or in6addr_any, or dynamic VIPA takeover is not wanted.
  • The IP address to which the application binds can be controlled by the user. The first explicit bind (the listening socket) of the application remains for the life of the application. Otherwise, the DVIPA is removed every time the DVIPA owning socket of the application is closed, and readded every time there is a new DVIPA owning socket (another explicit bind is done and the DVIPA does not exist).
  • Automatic deletion of the dynamic VIPA when the application is stopped is acceptable.
  • A specific dynamic VIPA address must be associated with a specific application.
  • The application is not APF-authorized, or not run under a user ID with superuser authority.
• When to use the VIPARANGE and the MODDVIPA utilities, or the SIOCSVIPA or SIOCSVIPA6 ioctl command to define a dynamic VIPA:
  • The application cannot bind to INADDR_ANY or in6addr_any, or dynamic VIPA takeover is not wanted. The IP address to which the application binds is known but cannot be controlled by the user. Automatic deletion of the dynamic VIPA when the application is stopped is not acceptable.
  • The application opens an AF_INET6 listener and binds to in6addr_any. The application needs to receive connections for multiple application-specific IPv4 and IPv6 destinations that are targeted for the port of this socket. The application can use MODDVIPA or the SIOCSVIPA and SIOCSVIPA6 ioctl command to create the IP address targets.

  The MODDVIPA utility or application that is issuing the ioctl command is to be run from an APF-authorized library and under a user ID with appropriate authority. See Use of the SIOCSVIPA or SIOCSVIPA6 ioctl command or Using the MODDVIPA utility.