Simple Network Paging Protocol (SNPP) is a protocol that defines a method by which a pager can receive a message over the Internet. It is supported by most major paging providers, and serves as an alternative to the paging modems used by many telecommunications services. The protocol was most recently described in RFC 1861. It is a fairly simple protocol that may run over TCP port 444 and sends out a page using only a handful of well-documented commands.
PortMap