Port 2517H.323 Annex E Call Signalling Transport

H.323 Annex E call-control signalling transport assigned for TCP and UDP communication.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 5/10
lookups: 0

also known as call-sig-trans, H.323 Annex E Call Control Signalling Transport

Technical Details

what runs on :2517

H.323 Annex E defines an alternative call-signalling transport for H.323 systems, using port 2517 over both TCP and UDP. It carries H.225.0 call-control signalling rather than RTP media; conventional H.323 deployments commonly use TCP 1720 for call setup, with additional dynamically negotiated channels for H.245 and media. Annex E support is implementation-dependent, and the port is not normally present on H.323 devices that do not enable this transport.

Security Information

exposure of :2517

risk score

5/ 10caution

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

network services averages 2.6 across 1,511 ports — this one sits 2.4 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

Annex E signalling is not encrypted by default, so exposed traffic may disclose call-control information and endpoint details. Internet exposure also lets scanners and attackers probe H.323 call-control behavior or consume signalling resources; it should normally be restricted to trusted peers or protected with a VPN, firewall rules, and application-layer authentication where supported.

Record

iana registry entry

port: :2517
service: H.323 Annex E Call Signalling Transport
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 5/10caution
category: Network Services Voice and Chat
usage: This port is used by H.323 systems that implement Annex E for transporting H.225.0 call-control signalling. Engineers are more commonly likely to encounter standard H.323 signalling on TCP 1720, making port 2517 relatively uncommon.
lookups: 0rank 993
added: 2026-08-24
updated: 2026-09-22
references: IANA service name registry — port 2517

Something wrong?

This record is maintained by the engineers who use port 2517. 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 2026-09-22.

01edit any field on a page of its own
02a model checks it for accuracy and spam
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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 :2517H.323 Annex E Call Signalling Transport

Technical Details

Security Information

Related Ports

Port 2517H.323 Annex E Call Signalling Transport