Rlogin

Rlogin (RFC 1282-ish — see below) gives single-sign-on terminal
access. Port 513/tcp. Mostly used by inter-BBS game servers
where one BBS launches a game on another and the player travels with
their identity intact.

How it works

The client opens a connection to port 513 and sends three null-
terminated strings:

\0 client-username \0 server-username \0 terminal/baud \0

The server reads them, validates against its allowlist, and drops the
user straight into the menu (or directly into a door if the rlogin
was for a specific game).

Synchronet game-server caveat

Synchronet-flavored rlogin uses an inverted field order vs the
standard:

password first, username second.

ANetBBS's outbound door_rlogin game type follows the Synchronet
convention. See Door Setup#rlogin doors for the details on the
remote-game flow.

Locally

For local user logins, ANetBBS uses rlogin to auto-login from the
Web Terminal and from MRC user-roster joins. The user types
nothing — their identity rides the rlogin handshake and they land
on the menu.