Internet-Security.com TCP port 87 details

TCP port 87 is the IANA-registered TTYLINK service, an early ARPANET terminal-to-terminal chat/link protocol.
It was implemented on DEC TOPS-20 systems (e.g., the TOPS-20 TTYLINK server) and other PDP-10 platforms used at institutions like MIT.
Some vintage UNIX environments also offered ttylink-compatible services, but the protocol is now effectively obsolete and rarely present on modern networks.
No notable contemporary software uses TCP/87 by default.
It is not broadly associated with specific exploitation campaigns beyond generic probing of uncommon open ports.

TCP 87