Port 1718H.323 Multicast Gatekeeper Discovery

H.323 multicast gatekeeper discovery uses this port to locate a gatekeeper on an H.323 network.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 2/10
lookups: 0

also known as h323gatedisc, H.323 gatekeeper discovery, H.225 RAS discovery

Technical Details

what runs on :1718

H.323 gatekeeper discovery uses H.225 RAS Gatekeeper Request (GRQ) messages, normally sent over UDP to the H.323 multicast address 224.0.1.41 on port 1718. A gatekeeper responds with Gatekeeper Confirm (GCF) or Gatekeeper Reject (GRJ), after which the endpoint uses UDP port 1719 for RAS exchanges and commonly TCP port 1720 for H.225 call signaling. Messages use ASN.1 PER encoding and are not encrypted by default; although IANA lists both TCP and UDP, multicast discovery is ordinarily a UDP operation.

Security Information

exposure of :1718

risk score

2/ 10safe

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

network services averages 3.2 across 842 ports — this one sits 1.2 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 port is intended for local H.323 network discovery, not direct Internet exposure. Unrestricted access can disclose gatekeeper and endpoint information or permit spoofed discovery responses, while legacy H.323 implementations may have additional protocol vulnerabilities; restrict it to trusted voice-network segments and filter multicast and unsolicited WAN traffic.

Record

iana registry entry

port: :1718
service: H.323 Multicast Gatekeeper Discovery
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 2/10safe
category: Network Services Voice and Chat
usage: H.323 endpoints use this service to discover an available gatekeeper, typically through a local multicast request. Engineers generally encounter it in legacy IP telephony, videoconferencing, and H.323 voice networks rather than on the public Internet.
lookups: 0rank 994
added: 2026-08-30
updated: 2026-08-30
references: IANA service name registry — port 1718

Something wrong?

This record is maintained by the engineers who use port 1718. 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 2026-08-30.

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risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :1718H.323 Multicast Gatekeeper Discovery

Technical Details

Security Information

Related Ports

Port 1718H.323 Multicast Gatekeeper Discovery