Well-known · Cross-platform

81 HTTP alt / Tor

TCP Unofficial
UDP —
SCTP —
DCCP —

What it is

Common alternate HTTP; also TorPark onion routing.

When / why

Secondary web listeners and proxies.

Protocol status detail

TransportStatusMeaning
TCP Unofficial Not assigned by IANA, but standardized, specified, or widely used on this port.
UDP — Not applicable for this transport.
SCTP — Not applicable for this transport.
DCCP — Not applicable for this transport.
« 80 HTTP 88 Kerberos »

Port range

Well-known (0–1023). System port for a core service. On Unix-like systems, binding it requires superuser privileges.

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