Registered · Cross-platform

3671 KNXnet/IP

TCP Yes
UDP Yes
SCTP —
DCCP —

What it is

KNX building automation over IP.

When / why

Smart-building control. Isolate.

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.
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Port range

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

Browse all ports →

Firewall rules for port 3671

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 3671

Allow TCP 3671 (KNXnet/IP). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 3671

Allow UDP 3671 (KNXnet/IP). 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="3671" protocol="tcp" accept'

Allow TCP 3671 (KNXnet/IP) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="3671" protocol="udp" accept'

Allow UDP 3671 (KNXnet/IP) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 3671 accept

Allow TCP 3671 (KNXnet/IP). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 3671 accept

Allow UDP 3671 (KNXnet/IP). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 3671 -j ACCEPT

Allow TCP 3671 (KNXnet/IP). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 3671 -j ACCEPT

Allow UDP 3671 (KNXnet/IP). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-knxnetip-3671 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 3671

Inbound rule for 3671 (KNXnet/IP). 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=3671,ToPort=3671,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 3671 (KNXnet/IP). 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=3671,ToPort=3671,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 3671 (KNXnet/IP). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-knxnetip-3671 --direction=INGRESS --action=ALLOW --rules=tcp:3671,udp:3671 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 3671 (KNXnet/IP). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow KNXnet/IP 3671/TCP" dir=in action=allow protocol=TCP localport=3671 remoteip=<source>

Inbound TCP 3671 (KNXnet/IP). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow KNXnet/IP 3671/UDP" dir=in action=allow protocol=UDP localport=3671 remoteip=<source>

Inbound UDP 3671 (KNXnet/IP). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow KNXnet/IP 3671/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 3671 -RemoteAddress <source>

Inbound TCP 3671 (KNXnet/IP). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow KNXnet/IP 3671/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 3671 -RemoteAddress <source>

Inbound UDP 3671 (KNXnet/IP). 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.