Registered · Cross-platform

1720 H.323 call signaling

TCP Yes
UDP —
SCTP —
DCCP —

What it is

H.323 Q.931 call setup.

When / why

VoIP/video call establishment.

Protocol status detail

TransportStatusMeaning
TCP Yes Assigned by IANA and standardized, specified, or widely used on this port.
UDP — Not applicable for this transport.
SCTP — Not applicable for this transport.
DCCP — Not applicable for this transport.

Port range

Registered (1024–49151). Assigned by IANA on request; usable without elevated privileges on most systems.

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Firewall rules for port 1720

Copy-ready inbound rules for the active transports. Replace every <source> placeholder with the specific host, subnet, or CIDR that should reach this port.

ufw

sudo ufw allow proto tcp from <source> to any port 1720

Allow TCP 1720 (H.323 call signaling). Replace <source> with the network/host that should reach it.

firewalld

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="1720" protocol="tcp" accept'

Allow TCP 1720 (H.323 call signaling) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 1720 accept

Allow TCP 1720 (H.323 call signaling). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 1720 -j ACCEPT

Allow TCP 1720 (H.323 call signaling). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-h323callsignaling-1720 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 1720

Inbound rule for 1720 (H.323 call signaling). Set <source> to a CIDR; lower priority number = higher precedence.

AWS Security Group

aws ec2 authorize-security-group-ingress --group-id <sg-id> --ip-permissions IpProtocol=tcp,FromPort=1720,ToPort=1720,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 1720 (H.323 call signaling). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-h323callsignaling-1720 --direction=INGRESS --action=ALLOW --rules=tcp:1720 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 1720 (H.323 call signaling). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow H.323 call signaling 1720/TCP" dir=in action=allow protocol=TCP localport=1720 remoteip=<source>

Inbound TCP 1720 (H.323 call signaling). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow H.323 call signaling 1720/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 1720 -RemoteAddress <source>

Inbound TCP 1720 (H.323 call signaling). Replace <source> with a host or subnet.

Rules are generated only for transports marked active for this port. They default to an inbound allow with an explicit source placeholder — never any. Review direction, scope, and rule precedence before applying in production.