Well-known · Cross-platform

524 NCP

TCP Yes
UDP Yes
SCTP
DCCP

What it is

NetWare Core Protocol.

When / why

Legacy Novell file/print access.

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.

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 524

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 524

Allow TCP 524 (NCP). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 524

Allow UDP 524 (NCP). 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="524" protocol="tcp" accept'

Allow TCP 524 (NCP) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="524" protocol="udp" accept'

Allow UDP 524 (NCP) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 524 accept

Allow TCP 524 (NCP). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 524 accept

Allow UDP 524 (NCP). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 524 -j ACCEPT

Allow TCP 524 (NCP). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 524 -j ACCEPT

Allow UDP 524 (NCP). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-ncp-524 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 524

Inbound rule for 524 (NCP). 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=524,ToPort=524,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 524 (NCP). 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=524,ToPort=524,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 524 (NCP). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-ncp-524 --direction=INGRESS --action=ALLOW --rules=tcp:524,udp:524 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 524 (NCP). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow NCP 524/TCP" dir=in action=allow protocol=TCP localport=524 remoteip=<source>

Inbound TCP 524 (NCP). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow NCP 524/UDP" dir=in action=allow protocol=UDP localport=524 remoteip=<source>

Inbound UDP 524 (NCP). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow NCP 524/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 524 -RemoteAddress <source>

Inbound TCP 524 (NCP). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow NCP 524/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 524 -RemoteAddress <source>

Inbound UDP 524 (NCP). 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.