Well-known · Cross-platform

992 Telnet over TLS

TCP Yes
UDP Yes
SCTP —
DCCP —

What it is

Telnet protocol over TLS/SSL.

When / why

Rarely used; SSH is the standard.

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.
« 991 NAS 993 IMAPS »

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 992

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 992

Allow TCP 992 (Telnet over TLS). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 992

Allow UDP 992 (Telnet over TLS). 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="992" protocol="tcp" accept'

Allow TCP 992 (Telnet over TLS) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="992" protocol="udp" accept'

Allow UDP 992 (Telnet over TLS) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 992 accept

Allow TCP 992 (Telnet over TLS). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 992 accept

Allow UDP 992 (Telnet over TLS). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 992 -j ACCEPT

Allow TCP 992 (Telnet over TLS). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 992 -j ACCEPT

Allow UDP 992 (Telnet over TLS). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-telnetovertls-992 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 992

Inbound rule for 992 (Telnet over TLS). 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=992,ToPort=992,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 992 (Telnet over TLS). 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=992,ToPort=992,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 992 (Telnet over TLS). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-telnetovertls-992 --direction=INGRESS --action=ALLOW --rules=tcp:992,udp:992 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 992 (Telnet over TLS). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow Telnet over TLS 992/TCP" dir=in action=allow protocol=TCP localport=992 remoteip=<source>

Inbound TCP 992 (Telnet over TLS). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow Telnet over TLS 992/UDP" dir=in action=allow protocol=UDP localport=992 remoteip=<source>

Inbound UDP 992 (Telnet over TLS). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow Telnet over TLS 992/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 992 -RemoteAddress <source>

Inbound TCP 992 (Telnet over TLS). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow Telnet over TLS 992/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 992 -RemoteAddress <source>

Inbound UDP 992 (Telnet over TLS). 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.