Well-known · Cross-platform

162 SNMP Trap

TCP Yes
UDP Yes
SCTP —
DCCP —

What it is

Asynchronous SNMP trap/notification delivery to the NMS.

When / why

Devices push alerts to the monitoring server on UDP/162.

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.
« 161 SNMP 177 XDMCP »

Port range

Well-known (0–1023). System port for a core service. On Unix-like systems, binding it requires superuser privileges.

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Firewall rules for port 162

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 162

Allow TCP 162 (SNMP Trap). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 162

Allow UDP 162 (SNMP Trap). 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="162" protocol="tcp" accept'

Allow TCP 162 (SNMP Trap) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="162" protocol="udp" accept'

Allow UDP 162 (SNMP Trap) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 162 accept

Allow TCP 162 (SNMP Trap). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 162 accept

Allow UDP 162 (SNMP Trap). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 162 -j ACCEPT

Allow TCP 162 (SNMP Trap). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 162 -j ACCEPT

Allow UDP 162 (SNMP Trap). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-snmptrap-162 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 162

Inbound rule for 162 (SNMP Trap). 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=162,ToPort=162,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 162 (SNMP Trap). 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=162,ToPort=162,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 162 (SNMP Trap). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-snmptrap-162 --direction=INGRESS --action=ALLOW --rules=tcp:162,udp:162 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 162 (SNMP Trap). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow SNMP Trap 162/TCP" dir=in action=allow protocol=TCP localport=162 remoteip=<source>

Inbound TCP 162 (SNMP Trap). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow SNMP Trap 162/UDP" dir=in action=allow protocol=UDP localport=162 remoteip=<source>

Inbound UDP 162 (SNMP Trap). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow SNMP Trap 162/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 162 -RemoteAddress <source>

Inbound TCP 162 (SNMP Trap). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow SNMP Trap 162/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 162 -RemoteAddress <source>

Inbound UDP 162 (SNMP Trap). 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.