Well-known · Cross-platform

101 NIC host name

TCP Yes
UDP Assigned
SCTP
DCCP

What it is

Hostname server (RFC 953).

When / why

Obsolete.

Protocol status detail

TransportStatusMeaning
TCP Yes Assigned by IANA and standardized, specified, or widely used on this port.
UDP Assigned Assigned by IANA, but not 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 101

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 101

Allow TCP 101 (NIC host name). 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="101" protocol="tcp" accept'

Allow TCP 101 (NIC host name) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 101 accept

Allow TCP 101 (NIC host name). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 101 -j ACCEPT

Allow TCP 101 (NIC host name). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-nichostname-101 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 101

Inbound rule for 101 (NIC host name). 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=101,ToPort=101,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 101 (NIC host name). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-nichostname-101 --direction=INGRESS --action=ALLOW --rules=tcp:101 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 101 (NIC host name). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow NIC host name 101/TCP" dir=in action=allow protocol=TCP localport=101 remoteip=<source>

Inbound TCP 101 (NIC host name). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow NIC host name 101/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 101 -RemoteAddress <source>

Inbound TCP 101 (NIC host name). 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.