Summary
As ElectricAccelerator (also CloudBees CD) is a distributed product which involves many computers in the network, it’s very important to make sure that the communications between these machines meet the requirement from the product.
Problem
It is quite common that a firewall exists between the computers in the company, especially in a big company which has complicated network settings for various reasons like security. Sometimes two computers seem connected (can ping each other), the communication between the two computers may not meet the requirements from ElectricAccelerator.
Solution
We need to make sure that all ports used by ElectricAccelerator are available and reachable. Specifically, we should check if a port in a host is available from another host.
There are many ways/tools to check this depending on the host OS from which you want to check the target host (the target host OS does NOT matter). Here’re some examples.
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From a host running Ubuntu . A simple telnet command is helpful in this case. The following test confirms that port 2411 of host "192.168.199.120" is available from "flowserver" . *
``` huafeng@flowserver:~$ telnet 192.168.199.120 2411 Trying 192.168.199.120... Connected to 192.168.199.120. Escape character is '^]'. Illegal message code: 218762506 Connection closed by foreign host. huafeng@flowserver:~$ ```
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Here’s an example of port 12345 of host "192.168.199.120" is NOT available from "flowserver" . *
``` huafeng@flowserver:~$ telnet 192.168.199.120 12345 Trying 192.168.199.120... telnet: Unable to connect to remote host: Connection refused huafeng@flowserver:~$ ```
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From a host running Windows 10 or Windows Server 2016 . I recommend to use the command "Test-NetConnection" in PowerShell.