Well-known · Linux/Unix

694 Linux-HA heartbeat

TCP Yes
UDP Yes
SCTP —
DCCP —

What it is

Heartbeat high-availability cluster messaging.

When / why

Cluster node liveness.

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.
« 691 MS Exchange Routing 698 OLSR »

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 694

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 694

Allow TCP 694 (Linux-HA heartbeat). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 694

Allow UDP 694 (Linux-HA heartbeat). 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="694" protocol="tcp" accept'

Allow TCP 694 (Linux-HA heartbeat) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="694" protocol="udp" accept'

Allow UDP 694 (Linux-HA heartbeat) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 694 accept

Allow TCP 694 (Linux-HA heartbeat). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 694 accept

Allow UDP 694 (Linux-HA heartbeat). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 694 -j ACCEPT

Allow TCP 694 (Linux-HA heartbeat). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 694 -j ACCEPT

Allow UDP 694 (Linux-HA heartbeat). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-linuxhaheartbeat-694 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 694

Inbound rule for 694 (Linux-HA heartbeat). 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=694,ToPort=694,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 694 (Linux-HA heartbeat). 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=694,ToPort=694,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 694 (Linux-HA heartbeat). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-linuxhaheartbeat-694 --direction=INGRESS --action=ALLOW --rules=tcp:694,udp:694 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 694 (Linux-HA heartbeat). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow Linux-HA heartbeat 694/TCP" dir=in action=allow protocol=TCP localport=694 remoteip=<source>

Inbound TCP 694 (Linux-HA heartbeat). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow Linux-HA heartbeat 694/UDP" dir=in action=allow protocol=UDP localport=694 remoteip=<source>

Inbound UDP 694 (Linux-HA heartbeat). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow Linux-HA heartbeat 694/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 694 -RemoteAddress <source>

Inbound TCP 694 (Linux-HA heartbeat). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow Linux-HA heartbeat 694/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 694 -RemoteAddress <source>

Inbound UDP 694 (Linux-HA heartbeat). 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.