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Port 51820: Windows dynamic RPC ports / WireGuard

Common Ports Reference: What runs on port 3389, 445 or 5985: common TCP and UDP ports for web, mail, Windows, AD, databases and VPNs, with security notes.

The ports that come up when opening a firewall, reading a scan or troubleshooting a connection: what runs on each, TCP or UDP, and what to watch out for. Search by number or name. Port numbers and service names were checked against IANA's port number registry; ports that are widely used but assigned by IANA to something else are marked unofficial.

Port number or name

51820 is a dynamic or private port (49152-65535): never assigned, used for the client side of connections. IANA's registry lists everything assigned to it: look up 51820 at IANA.

2 of 96 ports

What a domain controller and Windows servers listen on.

PortProtocolServiceWhat it's forIANA name
49152-65535
TCP
Windows dynamic RPC ports
The range Windows hands out to RPC services after 135. Firewalls between clients and domain controllers need it open (or RPC restricted to fixed ports).
unofficial

DNS, DHCP, time, SNMP, logging and VPNs.

PortProtocolServiceWhat it's forIANA name
51820
UDP
WireGuard
WireGuard's usual default; any port can be configured. Unofficial.
unofficial

Is port 51820 open on your network? Check it → · All common ports →