Observability

SolarWinds Agent Is Not Responding: TCP Port 17790 Not Listening

The SolarWinds Agent is installed on a node but not responding as expected.

First published date

8/31/2026 3:59 PM

Last published date

8/31/2026 3:59 PM

Overview

Symptoms:

  • The SolarWinds Agent service is running on the target server.

  • Remote troubleshooting is unavailable in the SolarWinds Platform Web Console.

  • The main polling engine cannot establish communication with the agent.

  • TCP port 17790 does not have a listening socket on the target server when server-initiated communication is being used.

Product section

Hybrid Cloud Observability

Resolution

Verify the following ports and directions:

  • TCP 17790: Allow connections from the SolarWinds Platform main polling engine to the agent target. This is required for server-initiated communication.

  • TCP 17778: Allow the agent target to connect to the SolarWinds Platform main polling engine. This is required for agent-initiated communication and is also used for agent communication and deployment in that mode.

Coordinate with the firewall or network team to verify and permit the required communication.

Verification

Run the following test from the main polling engine when server-initiated communication is configured:

Test-NetConnection -ComputerName **IpAddress** -Port 17790

A successful test should show:

TcpTestSucceeded : True

For agent-initiated communication, verify connectivity from 

**IpAddress**

to the main polling engine on TCP port 17778:

Test-NetConnection -ComputerName <main-poller-hostname-or-IP> -Port 17778

After the firewall rules are updated:

  • Confirm that the SolarWinds Agent service is running on the target server.

  • Confirm that the selected agent communication mode matches the firewall rules.

  • Recheck the agent status under Settings > All Settings > Node & Group Management > Manage Agents.

  • Confirm that remote troubleshooting is available and that the agent resumes communication.

Port requirements

Communication mode

Source

Destination

Port

Protocol

Requirement

Server-initiated

Main polling engine

Agent target

17790

TCP

Inbound on the agent target; used when the SolarWinds Platform server initiates communication.

Agent-initiated

Agent target

Main polling engine

17778

TCP

Outbound from the agent target and inbound on the SolarWinds Platform server; used when the agent initiates communication.

Port requirements can vary when custom agent ports or additional polling engines are configured. Update the firewall rules to match the actual communication mode and configured port.

 

Related SolarWinds documentation