Port 1701: L2TP

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

1701 is a registered port (1024-49151): assigned by IANA on request. IANA's registry lists everything assigned to it: look up 1701 at IANA.

1 of 96 ports

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

Port	Protocol	Service	What it's for	IANA name
1701	`UDP`	L2TP	L2TP VPNs, normally inside IPsec (with 500 and 4500).	`l2f`

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Network services 1