Error initializing RemoteWebDriver when Hub is hosted in a controlled network

[techie monk]

Hi,

I am running into an issue while trying to initialize RemoteWebDriver
when using with SeleniumGrid. I started the hub, registered the node
with it and verified that it shows up in the grid console. When I
execute my test it fails while trying to instantiate RemoteWebDriver.

HUB, NODE deployment
--------------------
Hub is running on a host in a controlled network (say NW1) listening
at 4444. Opening additional ports might be blocked in this network.
Node is running on a host in a different network (say NW2) listening
at 5555.

Does some one know what might be going wrong? How does the session get
established between the node and the hub? Would the grid spawn another
process on a separate port (on the same host as hub) with which the
remote web driver session would be established? If yes, what would be
the default port for this process?

Navigating through the stack trace I see the error happening in
RemoteWebDriver.class at this method call
Response response = execute(DriverCommand.NEW_SESSION,
ImmutableMap.of("desiredCapabilities", desiredCapabilities));

No issues when I run the test with both node, hub running on the same
host in NW2. It is when the hub is in NW1 and node in NW2 that I am
seeing this issue.


STACK TRACE
-----------
org.openqa.selenium.WebDriverException: Build info: version: '2.20.0',
revision: '16008', time: '2012-02-28 15:00:40'
System info: os.name: 'Linux', os.arch: 'amd64', os.version:
'2.6.32-38-generic', java.version: '1.6.0_27'
Driver info: driver.version: RemoteWebDriver
at
org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:
170)
at
org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:
123)
at
org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:
438)
at
org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:
139)
at
org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:
94)
at
org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:
102)
.....
Caused by: org.openqa.selenium.remote.ErrorHandler
$UnknownServerException: Build info: version: '2.20.0', revision:
'16008', time: '2012-02-28 15:00:40'
System info: os.name: 'Linux', os.arch: 'amd64', os.version:
'2.6.32-38-generic', java.version: '1.6.0_27'
Driver info: driver.version: unknown
at hudson.remoting.Command.<init>(Command.java:51)
at hudson.remoting.Channel$CloseCommand.<init>(Channel.java:842)
at hudson.remoting.Channel$CloseCommand.<init>(Channel.java:840)
at hudson.remoting.Channel.close(Channel.java:907)
at hudson.remoting.Channel.close(Channel.java:890)
at hudson.slaves.SlaveComputer.closeChannel(SlaveComputer.java:500)
at hudson.slaves.SlaveComputer.kill(SlaveComputer.java:481)
at hudson.model.AbstractCIBase.killComputer(AbstractCIBase.java:84)
at jenkins.model.Jenkins.cleanUp(Jenkins.java:2455)
at hudson.lifecycle.UnixLifecycle.restart(UnixLifecycle.java:71)
at jenkins.model.Jenkins$19.run(Jenkins.java:3056)

Appreciate any help.

Thanks