What is Port 162?

by David Brown | Published on June 27, 2025

Port 162 is the network port used to receive SNMP trap messages—alerts sent from devices like routers and switches to a central management system.

The Simple Network Management Protocol (SNMP) is a crucial component of most Internet Protocol (IP) networks. An SNMP server communicates with network devices through ports 161 and 162. In this article, we'll take a closer look at port 162.

Have a look at different network management options in the CBT Nuggets article API vs SNMP vs CLI: The Best Choice for Network Devices.

What is Port 162?

Port 162 is the default port for receiving SNMP trap messages. An SNMP trap is an automatic alert message sent from a client device to a centralized server. Port 161 handles most SNMP communication, such as polling, while port 162 is dedicated solely to alert messages from clients. 

Network devices such as routers, switches, and servers send alerts to the Network Management System (NMS) when a certain condition, such as an alarm threshold, is reached. Network administrators rely on these immediate notifications for real-time monitoring and management of their network infrastructure.

What is Port 162 Used For?

Port 162 allows traffic between any SNMP-capable network device and the network management system. It is primarily a User Datagram Protocol (UDP) port, but in some cases it is controlled by the Transmission Control Protocol (TCP). UDP traffic is connectionless and less reliable than TCP traffic. Port 162 pushes alerts from the network device to the SNMP server.

Common Applications of Port 162

SNMP traps on port 162 can be used to report hardware malfunctions, interface failures, security incidents, and environmental alerts. SNMP is commonly used in a variety of software applications:

• SolarWinds uses a dedicated trap service to receive and process trap messages. SNMP trap messages are displayed on a dashboard and may be stored for further processing and analysis.

• Nagios is an open-source network monitoring and alerting system. Nagios primarily receives traps on port 162, but may also receive notifications about trap status changes.

• Paessler Router Traffic Grapher (PRTG) is network monitoring software developed by Paessler GmbH. It monitors network conditions like bandwidth usage and uptime and collects statistics from various network devices. PRTG uses the SNMP Trap Receiver sensor to listen on port 162 and receive traps, allowing it to react to events without actively polling the devices.

And, of course, SNMP traps coming across port 162 include a variety of network devices, such as:

• Routers 

• Switches 

• Servers 

• Firewalls 

• Wireless access points 

• Printers

• Cloud services (e.g., Amazon Web Services)

Below is a display of the SolarWinds application taken from their website: 

Learn more about SNMP tools from the CBT Nuggets article 6 Best SNMP Tools for Network Monitoring and Management.

Security Considerations of Port 162

The first security consideration for traffic on port 162 is the SNMP version used. Three versions of SNMP are currently available.

SNMPv1

This was the first iteration of SNMP, introduced in the late 1980s. It uses plaintext community strings for access control—something like a shared password. SNMPv1 does not have encryption or authentication, and it can be easily intercepted. 

SNMPv2c

Introduced in the early 1990s, SNMPv2c improved performance and error handling but did not significantly improve security.

SNMPv3

The latest version of SNMP offers strong security, with potential for authentication as well as encryption. SNMPv3 supports three security levels, each combining different levels of authentication and privacy (encryption):

• noAuthNoPriv: No authentication or encryption; not secure

• authNoPriv: Authentication but no encryption; also not secure

• authPriv: Includes authentication and encryption

Authentication uses secure hashing protocols, such as Message Digest 5 (MD5) or Secure Hash Algorithm (SHA-1 or SHA-2). Encryption protocols include the legacy Data Encryption Standard (DES) and the modern Advanced Encryption Standard (AES). SNMPv3 with authPriv level is recommended. 

Another security consideration is firewall protection. Port 162 traffic should be firewalled and filtered to allow only trusted sources.

Read more about How to Configure SNMPv3 and How It Works in this article.

Port 161 vs. Port 162

Port 161 polls devices and requests data, while port 162 is used by devices to voluntarily send traps to the server based on events that have occurred. The server receives those notifications over port 162. 

Port 161 traffic is SNMP manager-initiated, while port 162 traffic is device-initiated. Port 161 asks questions, while port 162 offers unsolicited answers. The following table may make this clearer.

Port 162 FAQs

What’s the Difference Between SNMP Traps and Polling?

SNMP traps are unsolicited messages sent by devices (on port 162) when an event occurs. SNMP polling is a scheduled process performed by the network management system (NMS). Polling involves sending requests to devices (via port 161) to check their status or retrieve data. Traps are like a push notification, while polling is like asking for updates.

Is Port 162 Secure to Use?

That depends on the SNMP version and configuration used. SNMPv1 and SNMPv2c offer no real security, while SNMPv3 offers security based on the configured level. For best results, use SNMPv3 with authPriv and restrict access to trusted IP addresses using firewalls or access control lists.

Can SNMP Work Without Port 162?

Yes, SNMP port 161 works without port 162. But that covers only part of network management. Polling is a scheduled process. The SNMP manager will not receive real-time alerts from devices unless port 162 is used. 

Conclusion

The key benefit of SNMP port 162 is the real-time monitoring of the devices under network management. It is possible for network devices to use agents to send traps to an SNMP manager without port 162 on the device, but the SNMP manager will still need to have port 162 enabled to receive them. 

Because of security concerns, it is critical that modern networks use SNMPv3 configured with the authPriv level. When implemented properly, Port 162 remains a useful communication channel for modern networks.