Port 513 (login, who)

Document v1 · published by Koskamo · updated 2026-10-04

Port 513 is an IANA System Port assigned to login and who over TCP and UDP.

Port: 513
Service login: TCP — remote login a la telnet; automatic authentication performed based on priviledged port numbers and distributed data bases which identify "authentication domains"
Service who: UDP — maintains data bases showing who's logged in to machines on a local net and the load average of the machine
Range: System Ports (0–1023)

Source and provenance

Original source: www.iana.org
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: IANA Service Name and Transport Protocol Port Number Registry (iana.org/assignments/service-names-port-numbers), system ports 0-1023; registry data reproduced verbatim with references

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Version history

Published by Koskamo2026-10-04
Version 1