Port 3222Gateway Load Balancing Protocol (GLBP)

Cisco GLBP uses LAN control messages to provide redundant, load-balanced default gateways.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 4/10
lookups: 0

also known as glbp, Cisco GLBP

Technical Details

what runs on :3222

Although IANA lists both TCP and UDP for this assignment, deployed GLBP uses UDP port 3222 for control traffic; a TCP listener on this port should be identified separately. GLBP routers exchange messages over the local network, normally using multicast address 224.0.0.102. The Active Virtual Gateway assigns virtual MAC addresses to Active Virtual Forwarders and answers ARP requests for the shared virtual gateway IP, allowing hosts to use different forwarding routers while retaining gateway redundancy. Cisco defaults commonly use 3-second hello and 10-second hold timers.

Security Information

exposure of :3222

risk score

4/ 10caution

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

network services averages 2.7 across 1,372 ports — this one sits 1.3 above.

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

GLBP traffic is not encrypted, and the protocol is intended for a local LAN rather than the public internet. A rogue or compromised device on the same network may attempt to interfere with gateway election or forwarding and redirect or disrupt traffic; configure GLBP authentication where supported and restrict control traffic to trusted segments. Internet-wide scans generally will not find a normal GLBP deployment because its control messages are LAN multicast, not a public TCP service.

Record

iana registry entry

port: :3222
service: Gateway Load Balancing Protocol (GLBP)
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 4/10caution
category: Network Services
usage: GLBP is a Cisco-proprietary first-hop redundancy protocol used between routers on a LAN. Hosts use a shared virtual IP as their default gateway, while GLBP distributes forwarding across routers. Engineers typically encounter it in Cisco router configurations and LAN captures, not as an internet-facing service.
lookups: 0rank 993
added: 2026-09-28
updated: 2026-09-28
references: IANA service name registry — port 3222

Something wrong?

This record is maintained by the engineers who use port 3222. 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 2026-09-28.

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edit this record →back to the registry

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risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :3222Gateway Load Balancing Protocol (GLBP)

Technical Details

Security Information

Related Ports

Port 3222Gateway Load Balancing Protocol (GLBP)