Well-known · Cross-platform

631 IPP / CUPS

TCP Yes
UDP Yes
SCTP —
DCCP —

What it is

Internet Printing Protocol; CUPS administration on Linux/macOS.

When / why

Modern network printing and print-server admin.

Protocol status detail

TransportStatusMeaning
TCP Yes Assigned by IANA and standardized, specified, or widely used on this port.
UDP Yes Assigned by IANA and standardized, specified, or widely used on this port.
SCTP — Not applicable for this transport.
DCCP — Not applicable for this transport.
« 625 Open Directory Proxy 636 LDAPS »

Port range

Well-known (0–1023). System port for a core service. On Unix-like systems, binding it requires superuser privileges.

Browse all ports →

Firewall rules for port 631

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 631

Allow TCP 631 (IPP / CUPS). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 631

Allow UDP 631 (IPP / CUPS). 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="631" protocol="tcp" accept'

Allow TCP 631 (IPP / CUPS) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="631" protocol="udp" accept'

Allow UDP 631 (IPP / CUPS) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 631 accept

Allow TCP 631 (IPP / CUPS). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 631 accept

Allow UDP 631 (IPP / CUPS). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 631 -j ACCEPT

Allow TCP 631 (IPP / CUPS). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 631 -j ACCEPT

Allow UDP 631 (IPP / CUPS). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-ippcups-631 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 631

Inbound rule for 631 (IPP / CUPS). 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=631,ToPort=631,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 631 (IPP / CUPS). Replace <source-cidr> (e.g. 10.0.0.0/16).

aws ec2 authorize-security-group-ingress --group-id <sg-id> --ip-permissions IpProtocol=udp,FromPort=631,ToPort=631,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 631 (IPP / CUPS). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-ippcups-631 --direction=INGRESS --action=ALLOW --rules=tcp:631,udp:631 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 631 (IPP / CUPS). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow IPP / CUPS 631/TCP" dir=in action=allow protocol=TCP localport=631 remoteip=<source>

Inbound TCP 631 (IPP / CUPS). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow IPP / CUPS 631/UDP" dir=in action=allow protocol=UDP localport=631 remoteip=<source>

Inbound UDP 631 (IPP / CUPS). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow IPP / CUPS 631/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 631 -RemoteAddress <source>

Inbound TCP 631 (IPP / CUPS). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow IPP / CUPS 631/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 631 -RemoteAddress <source>

Inbound UDP 631 (IPP / CUPS). 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.