Disclosed are methods and apparatus for network wide discovery of service ports of a gateway device in a storage area network (SAN) that are available for use by hosts on a first particular network segment, for example, for accessing storage devices in the SAN. The hosts of the first Internet Protocol (IP) network segment implement an IP and not a fiber channel protocol, while devices in the SAN (and possibly other hosts on other network segments) implement a fiber channel protocol. The particular network segment may also be isolated from other network segments that are each in communication with a different gateway device or set of service ports than the first network segment. In general, available ports are discovered with respect to a particular network segment, such as the first network segment. That is, only the service ports that are capable of communication with the first network segment are discovered to be available for the hosts of such first network segment. Other service ports are not capable of communication with the first network segment. For example, these service ports are configured to communicate with another network segment that is isolated from the first network segment. These other service ports are not discovered to be available to hosts on the first network segment.