Observability

DHCP User Experience Monitor times out when adding a DHCP Server

The SolarWinds DHCP User Experience Monitor could not add or test the DHCP server because the required DHCP traffic was not permitted between the Main Polling Engine (MPE) and the DHCP server. PortQry reported UDP ports 67 and 68 as NOT LISTENING on the target DHCP server. After the required traffic was allowed, the monitor test completed successfully.

First published date

9/29/2026 4:25 PM

Last published date

9/29/2026 4:25 PM

Overview

The DHCP User Experience Monitor times out when testing the server.

PortQry connectivity test results indicate that DHCP traffic is not successfully passing between the MPE and the DHCP server. Although UDP services may not always respond to a generic port query in the same way as TCP services, the result is consistent with the observed monitor timeout.

Symptoms

  • The DHCP server could not be added or tested under SAM DHCP User Experience Monitoring.

  • The monitor test timed out.

  • PortQry reports the following ports as NOT LISTENING on the target server:

    • UDP 67 — DHCP server requests

    • UDP 68 — DHCP server responses

Product section

Hybrid Cloud Observability

Resolution

  • Log in to the MPE/polling server and open File Explorer.
  • Browse to the folder where PortQry is installed/extracted, then open PortQueryUI.exe.
  • In Destination IP or FQDN, enter the DHCP server IP.
  • Select Manually input query ports, enter 67,68, and select UDP.
  • Click Query.
  • Check the results for UDP ports 67 and 68. Repeat after firewall changes if either port shows NOT LISTENING or times out.

Coordinate with the internal firewall and server administration teams to allow the required DHCP traffic between the MPE and the DHCP server:

  • Allow UDP 67 from the MPE to the DHCP server.

  • Allow UDP 68 from the DHCP server back to the MPE.

  • Ensure that the return traffic is permitted when using Relay Agent mode.