Port 4755GRE-in-UDP with DTLS

UDP port 4755 carries GRE tunnel traffic protected by DTLS.

transport: udp
in transit: encrypted
assignment: official
risk: 2/10
lookups: 0

also known as gre-udp-dtls, GRE-in-UDP encapsulation with DTLS

Technical Details

what runs on :4755

The endpoint listens on UDP port 4755 for GRE-in-UDP traffic protected by Datagram Transport Layer Security (DTLS). A DTLS handshake negotiates the security association; subsequent datagrams carry the GRE-in-UDP payload under DTLS protection. The related GRE-in-UDP service without this DTLS protection uses UDP port 4754. The actual handshake and cryptographic parameters depend on the implementation and its configuration.

Security Information

exposure of :4755

risk score

2/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

security averages 3.1 across 382 ports — this one sits 1.1 below.

in transit

encrypted

payloads are protected on the wire

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

DTLS is intended to provide confidentiality and integrity for tunnel traffic, but the protection and peer authentication available depend on the negotiated configuration and credentials. Restrict this endpoint to expected tunnel peers and use appropriate authentication; an exposed listener can still be probed or targeted for denial of service. This is a specialized, rarely observed service rather than a commonly exposed public service.

Record

iana registry entry

port: :4755
service: GRE-in-UDP with DTLS
transport: UDP
encryption: tls / encrypted
assignment: iana registered
risk: 2/10safe
category: Security Network Services
usage: This is a standardized port for GRE-in-UDP encapsulation protected with DTLS, intended for network tunnel endpoints rather than a general-purpose client service. It is likely to be encountered in purpose-built or managed network overlays; it was not observed open in the cited internet-wide scan data.
lookups: 0rank 993
added: 2026-10-06
updated: 2026-10-06
references: IANA service name registry — port 4755
RFC 8086

Something wrong?

This record is maintained by the engineers who use port 4755. Every field on it is editable — change what's wrong, say how you know, and a reviewer publishes it, usually within a minute. Last touched 2026-10-06.

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edit this record →back to the registry

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risk mix of the 8 listed

caution100%

2 of 8 encrypted

Port :4755GRE-in-UDP with DTLS

Technical Details

Security Information

Related Ports

Port 4755GRE-in-UDP with DTLS