[JENKINS-66736] Connect to Windows Agent failing with "different server found for same hostname"

Agent launches and begins to connect, but then log on master/controller shows error below and eventually Windows agent connection times out as failure. No Windows agents are thus available to perform build tasks.

{{2021-09-26 14:28:22.740+0000 [id=3752]  INFO    c.h.smbj.connection.Connection#close: Closed connection to 10.134.37.223

2021-09-26 14:28:22.740+0000 [id=3901]  INFO    c.h.smbj.transport.PacketReader#run: Thread[Packet Reader for 10.134.37.223,5,main] stopped.

2021-09-26 14:28:22.740+0000 [id=3752]  WARNING h.plugins.ec2.win.WinConnection#pingFailingIfSSHHandShakeError: Failed to verify connectivity to Windows agent

com.hierynomus.protocol.transport.TransportException: Different server found for same hostname '10.134.37.223', disconnecting...

at com.hierynomus.smbj.connection.SMBProtocolNegotiator.initializeOrValidateServerDetails(SMBProtocolNegotiator.java:232)

at com.hierynomus.smbj.connection.SMBProtocolNegotiator.negotiateDialect(SMBProtocolNegotiator.java:83)

at com.hierynomus.smbj.connection.Connection.connect(Connection.java:141)

at com.hierynomus.smbj.SMBClient.getEstablishedOrConnect(SMBClient.java:96)

at com.hierynomus.smbj.SMBClient.connect(SMBClient.java:71)

at hudson.plugins.ec2.win.WinConnection.pingFailingIfSSHHandShakeError(WinConnection.java:136)

at hudson.plugins.ec2.win.EC2WindowsLauncher.connectToWinRM(EC2WindowsLauncher.java:189)

at hudson.plugins.ec2.win.EC2WindowsLauncher.launchScript(EC2WindowsLauncher.java:52)

at hudson.plugins.ec2.EC2ComputerLauncher.launch(EC2ComputerLauncher.java:48)

at hudson.slaves.SlaveComputer.lambda$_connect$0(SlaveComputer.java:295)

at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)

at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:80)

at java.util.concurrent.FutureTask.run(FutureTask.java:266)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)

at java.lang.Thread.run(Thread.java:748)}}

The issue seems tied to this method where the cached server is being validated and coming back as invalid from here.

This seems to be regression in 1.64 version of the plugin as nothing in our environment has changed since this was validated as working with version 1.61.

---
Originally reported by guy_davis, imported from: Connect to Windows Agent failing with "different server found for same hostname"

• assignee: raihaan
  
• status: Open
  
• priority: Blocker
  
• component(s): ec2-plugin
  
• label(s): plugin, windows
  
• resolution: Unresolved
  
• votes: 0
  
• watchers: 3
  
• imported: 2025-12-06
  

Raw content of original issue

Agent launches and begins to connect, but then log on master/controller shows error below and eventually Windows agent connection times out as failure.  No Windows agents are thus available to perform build tasks.




{{2021-09-26 14:28:22.740+0000 [id=3752]  INFO    c.h.smbj.connection.Connection#close: Closed connection to 10.134.37.223

2021-09-26 14:28:22.740+0000 [id=3901]  INFO    c.h.smbj.transport.PacketReader#run: Thread[Packet Reader for 10.134.37.223,5,main] stopped.

2021-09-26 14:28:22.740+0000 [id=3752]  WARNING h.plugins.ec2.win.WinConnection#pingFailingIfSSHHandShakeError: Failed to verify connectivity to Windows agent

com.hierynomus.protocol.transport.TransportException: Different server found for same hostname '10.134.37.223', disconnecting...

        at com.hierynomus.smbj.connection.SMBProtocolNegotiator.initializeOrValidateServerDetails(SMBProtocolNegotiator.java:232)

        at com.hierynomus.smbj.connection.SMBProtocolNegotiator.negotiateDialect(SMBProtocolNegotiator.java:83)

        at com.hierynomus.smbj.connection.Connection.connect(Connection.java:141)

        at com.hierynomus.smbj.SMBClient.getEstablishedOrConnect(SMBClient.java:96)

        at com.hierynomus.smbj.SMBClient.connect(SMBClient.java:71)

        at hudson.plugins.ec2.win.WinConnection.pingFailingIfSSHHandShakeError(WinConnection.java:136)

        at hudson.plugins.ec2.win.EC2WindowsLauncher.connectToWinRM(EC2WindowsLauncher.java:189)

        at hudson.plugins.ec2.win.EC2WindowsLauncher.launchScript(EC2WindowsLauncher.java:52)

        at hudson.plugins.ec2.EC2ComputerLauncher.launch(EC2ComputerLauncher.java:48)

        at hudson.slaves.SlaveComputer.lambda$_connect$0(SlaveComputer.java:295)

        at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)

        at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:80)

        at java.util.concurrent.FutureTask.run(FutureTask.java:266)

        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)

        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)

        at java.lang.Thread.run(Thread.java:748)}}





The issue seems tied to this method  where the cached server is being validated and coming back as invalid from here.


This seems to be regression in 1.64 version of the plugin as nothing in our environment has changed since this was validated as working with version 1.61.  

environment

```
Jenkins version: 2.303.1

ec2-plugin: 1.64

Master/Controller OS: CentOS 7 (fully up-to-date)

Slave/Agent OS: Windows Server 2019
```

Start with the Windows connection path in WinConnection.java and EC2WindowsLauncher.java, then inspect the referenced SMBProtocolNegotiator.java validation path. Reproduce the Windows agent connection failure and compare behavior between ec2-plugin 1.61 and 1.64; done means the agent connects without the reported timeout or server-identity error.

Written by the indexing model from the issue text.