At the bottom of the table, there is also a section of general top level domains, based on the information available at rs.internic.net. This includes 'telnet', 'ftp', and internet E-mail. If this is not preceded by FI or B, it means that the connection may be a UUCP connection. An asterisk is included after FI or B for consistency. In other cases, it is a courtesy domain provided for commercial reasons which may, or may not be seen as a legitimate use of that top level domain.
P stands for provisional connection.
It is assumed that the FIDO connection in this case is stable and reliable. It is generally possible to assume that wherever there is a U.S. military base, there will be a node reachable through gateways. While those types of network are fading fast due to their high cost compared to the Internet, some regions of the world are still reacheable only via such networks. X.400 E-mail is usually charged to someone and if the telecommunication carrier cannot find someone to pay for the message transfer, it will reject it. The situation changes from day to day.