SCOM agent Installation on Linux Machine

Mahankali, Sai 0 Reputation points
2026-03-17T07:25:30.9833333+00:00

Hello Team,

We are facing issue with a Linux machine, where the agent was already reporting healthy, post patching SCOM agent was broke. When we try to install again getting error as"The target address is unreachable". Port 22 and 1270 is open, ping is working.

Could someone please help on troubleshooting.

This is the detailed error:

WinRM cannot complete the operation. Verify that the specified computer name is valid, that the computer is accessible over the network, and that a firewall exception for the WinRM service is enabled and allows access from this computer. By default, the WinRM firewall exception for public profiles limits access to remote computers within the same local subnet.

It is possible that:

  1. The destination computer is unreachable (because it is down, or due to a firewall issue).
  2. The destination certificate is signed by another certificate authority not trusted by the management server.
  3. The destination has an invalid certificate, e.g., its common name (CN) does not match the fully qualified domain name (FQDN) used for the connection.
  4. The servers in the resource pool have not been configured to trust certificates signed by other servers in the pool.
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3 answers

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  1. Mahankali, Sai 0 Reputation points
    2026-03-23T07:35:32.2566667+00:00

    Tried the troubleshooting that AI suggest and everything looks fine but still unable to install the agent.

    Need assistance on troubleshooting it pls.

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  2. SChalakov 10,861 Reputation points MVP Volunteer Moderator
    2026-03-18T10:42:22.49+00:00

    Hi Sai,

    i would follow the recommendations given by the Q&A Assist first, those are applicable. Please write back after you have done all those checks and in case you still face an issue. Regards

    Stoyan

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  3. AI answer

    2026-03-17T07:25:52.26+00:00

    Use the error text “The target address is unreachable” and the WinRM message to focus on WS-Man connectivity and certificate/DNS validation between the SCOM management server and the Linux agent.

    Troubleshooting steps:

    1. Verify name resolution (forward and reverse DNS)
      • If discovery is done by IP address, ensure reverse lookup exists:
        • The IP must resolve back to the correct hostname in DNS.
      • If discovery is done by FQDN, ensure forward lookup exists:
        • The FQDN must resolve to the correct IP.
      • Also verify that forward and reverse DNS entries match each other; mismatches can cause discovery failures.
      • Fix any DNS issues (missing or incorrect A/PTR records) and retry discovery.
    2. Confirm reachability and firewall for WS-Man port 1270
      • Even if ping works and ports 22/1270 appear open, confirm from each SCOM management server in the UNIX/Linux resource pool:
        • Test TCP connectivity to port 1270 on the Linux host.
        • Ensure no network or host-based firewall is blocking TCP 1270.
      • The error “The target address is unreachable” is explicitly associated with:
        • Host unreachable (network or host outage), or
        • Firewall blocking TCP 1270.
    3. Validate that the UNIX/Linux agent is installed and running
      • After patching, confirm on the Linux machine that the SCOM/OMS agent services are running and listening on 1270.
      • If the agent was manually installed, ensure it has not been removed or corrupted by patching.
    4. Check certificate validity and trust
      • Since the error text mentions certificate issues, verify:
        • The agent certificate on the Linux host is valid and correctly signed by the SCOM management server.
        • The CN/FQDN in the certificate matches the hostname/FQDN used in discovery.
        • The management servers in the UNIX/Linux resource pool trust the CA that signed the Linux agent certificate.
      • If the agent was reinstalled manually, follow the documented steps to:
        • Generate the certificate on the Linux host.
        • Copy it to the management server and sign it with scxcertconfig.
        • Copy the signed certificate back, replace the old one, and restart the agent.
    5. Re-run discovery with the correct discovery type
      • After confirming agent, certificates, and connectivity:
        • Use the Discovery Wizard with Discover only computers with the UNIX/Linux agent installed (or Only computers with an installed agent and signed certificate if the certificate is already signed).
      • If WS-Man–only discovery fails because the certificate is not signed, either:
        • Manually sign the certificate, or
        • Change discovery type to Discover all computers so the wizard can perform certificate signing.
    6. Review logs on both sides
      • On the SCOM management server:
        • Check Operations Manager and Windows Remote Management logs for detailed WS-Man errors.
      • On the Linux host:
        • Check system/messages logs for any SCX/OMS/WS-Man–related errors and for firewall or PAM-related denials.

    These steps address the documented causes for “target address is unreachable” and WinRM/WS-Man failures during UNIX/Linux agent discovery: DNS/name resolution issues, network/firewall blocking of port 1270, agent not running, and certificate/trust problems.

    References:

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