Agent installation issue

zap123

Lets say we have 3 domain ms A, B and C

A has solarwinds setup - 1 main polling engine, 1 web, 1 db and 4 Ape

We have domain B and solarwindmain polling engine is connected to 1 B’s Ape

now we are adding 3rd domain C and when we are adding nodes with WMI we are able to add. When we install agent we are able to to install but in solarwinds setting it shows agent cannot connect.

when i tried on one of the C server to install agent manually i am getting error

Failed: handshake:

An existing connection was forcibly closed by the remote host

[system:10054]

additionally-
17778 is working

Ping is working

mr.castaneda

Hi @zap123,

Since ping and TCP port 17778 are both passing, your layer-4 network connectivity is good. The Failed: handshake [system:10054] error indicates that the TCP connection opens, but the TLS/SSL certificate exchange is being abruptly terminated or rejected during negotiation.

In multi-domain / isolated network setups like yours, this usually comes down to one of the following:

1. Firewall / SSL Deep Packet Inspection (DPI)
   • Next-gen firewalls (Palo Alto, Fortinet, etc.) sitting between Domain C and Domain A/B often attempt to inspect or intercept traffic on port 17778. Because the SolarWinds Agent uses mutual certificate authentication, SSL inspection breaks the handshake and drops the connection.
   • Fix: Ensure an SSL/TLS inspection bypass/exception is in place for port 17778 between Domain C and your Polling Engine(s).
2. TLS Protocol / Cipher Suite Mismatch
   • If Domain C servers have hardened GPOs (e.g., TLS 1.0/1.1 disabled and specific TLS 1.2 cipher suites enforced), ensure the target Polling Engine and the Domain C servers support matching TLS 1.2 cipher suites.
3. Target Polling Engine & Communication Mode
   • Double-check which Polling Engine the manual agent installer was pointed to (FQDN vs. IP). If Domain C cannot resolve the FQDN of the specific APE or Main Polling Engine, or if NAT is in place, try using the direct IP address of the intended Polling Engine.
   • Make sure the agent is set to Agent-Initiated (outbound port 17778 to poller). If it’s set to Server-Initiated, the poller will need inbound access to the agent on port 17790.
4. Stale Agent Certificates (if previously installed or cloned)
   • If the agent was previously attempted or the VM was cloned from a template with an old agent:
     1. Stop the SolarWinds Agent service and uninstall the agent.
     2. Delete the contents of C:\ProgramData\SolarWinds\Agent\.
     3. Re-download a fresh manual installer from the Web Console and run it again.

Next step to check logs:
On the Domain C server, take a look at C:\ProgramData\SolarWinds\Logs\Agent\SolarWinds.Agent.log — it will give you the exact point where the TLS negotiation fails.

Hope this helps!