Port 3503MPLS LSP Ping

MPLS LSP Ping uses this port for echo requests and replies that verify label-switched paths.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 3/10
lookups: 0

also known as MPLS LSP Echo, MPLS echo

Technical Details

what runs on :3503

MPLS LSP Ping, specified by RFC 4379 and updated by RFC 8029, carries MPLS echo request and reply messages, normally over UDP destination port 3503. The messages contain structured OAM fields such as a version, message type, return code, and sub-TLVs identifying the target FEC or LSP; LSP traceroute uses related echo messages with controlled MPLS TTL processing. IANA lists both TCP and UDP for this service, but standard MPLS LSP Ping operation is UDP-based and is not an encrypted protocol.

Security Information

exposure of :3503

risk score

3/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

security averages 3.5 across 269 ports — this one sits 0.5 below.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

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

reachable over

tcp · udp

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

security overview

This is an infrastructure diagnostic endpoint and should generally be reachable only from trusted provider-network or management peers, not from the public Internet. Unrestricted access can disclose MPLS topology and forwarding information and may permit diagnostic-request or response-amplification abuse, although the assignment is uncommon on Internet-facing hosts.

Record

iana registry entry

port: :3503
service: MPLS LSP Ping
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 3/10caution
category: Security Network Services
usage: Network operators use MPLS LSP Ping to test whether an MPLS label-switched path reaches its intended egress and to diagnose forwarding faults. It is primarily encountered as UDP-based provider-network OAM traffic between MPLS routers, rather than as a general application service.
lookups: 0rank 994
added: 2026-09-04
updated: 2026-09-04
references: IANA service name registry — port 3503
RFC 8029

Something wrong?

This record is maintained by the engineers who use port 3503. 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 2026-09-04.

01edit any field on a page of its own
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edit this record →back to the registry

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risk mix of the 8 listed

caution100%

3 of 8 encrypted

Port :3503MPLS LSP Ping

Technical Details

Security Information

Related Ports

Port 3503MPLS LSP Ping