Telnet can be used to determine connectivity between CCS components.
Common listening ports for the different CCS components:
All CCS Managers: 5600
All Windows agents: 5601
All UNIX/Linux agents: 5600
It is best to test communication from each server that is running a CCS components. Example: from ManagerA to ManagerB, and then from ManagerB to ManagerA.
Start -> Run -> cmd (to open a command prompt. You might have to open the cmd 'As administrator')
telnet <target_server_hostname> <listening_port>
(NOTE: You can use the hostname, FQDN, or IP of the CCS component you would like to connect to can be used to test)
telnet mgrccstest 5600 (this example shows an attempt to telnet to the target server MGRCCSTEST using port 5600)
If a blank screen appears with no errors a telnet session has been established. Press another key to break the connection and return to a command prompt.
Just running Telnet and connecting to a server is only part of the test. If the DNS is incorrect, or if there are firewalls between the originating server and the target server, it can seem to connect but it might not be the correct server. Checking the logs of the target server can confirm that the telnet did indeed connect to the target server is required.
On the target server, open the C:\Program Files (x86)\Symantec\CCS\Reporting and Analytics\ESM\system\<hostname>\esmmanager.log. Scroll to the bottom and see if you see a generic connection attempt like the following:
 [2020/07/23 16:55:21:015] [CRITICAL] Scheduler: connection handshaking failed.
csp__server_handshake: error reading version from client
buffer is not large enough (data length = 3338, buffer size = 2064)
Note the date/time in the entry above on the target server, and compare that to when you ran the telnet command on the originating server. If it matches then it did connect to the target server correctly.
Firewalls between the servers may seem to allow the connectivity to be successful, but the CCS components will still not be able to function correctly. If you are getting the following error, this indicates that the two CCS components are able to connect, but firewall(s) (including the local firewall on the target server) may be impacting the packets and CCS is not able to validate the connection.
 [2020/07/24 17:32:40:294] [INFO] TCP server: 2020/07/24 <IP>: Connect from <IP_removed>
 [2020/07/24 17:32:40:294] [ERROR] TCP server: common port - failed to read initial few bytes from the socket with error 10054
 [2020/07/24 17:32:40:294] [ERROR] TCP server: common port - The CCS manager failed to validate the inbound connection. Ignoring the connection.
If you see the above error in the esmmanager.log file, you typically have firewall(s) impacting the packets. Contact your network administrator to allow the required ports for CCS to work correctly.