A network application no longer works on computers where Symantec Endpoint Protection (SEP) and its firewall component is installed.
If you uninstall the SEP firewall component, the network application works normally.
The SEP firewall may block network traffic that the network application requires to function properly.
To determine whether the SEP firewall blocks network traffic, create a rule that allows all network traffic through the firewall, then test the rule.
If the application issue is resolved by adding this rule, reconfigure the SEP firewall to allow the network traffic.
WARNING: Creating the Allow All rule is a troubleshooting step only, and is not a resolution to this issue. Leaving an Allow All rule permanently in place significantly reduces the computer's security posture.
Once you have created the Allow All rule, test the network application to confirm that the application works. If the application works, the original firewall ruleset configuration does not allow network traffic through to the application.
Next, remove the Allow All rule. You will need to create an additional firewall rule (or modify an existing rule) to allow the application's network traffic through SEP's firewall. If you do not know the ports and protocols the application uses, consult the application vendor's documentation.
Most vendors will specify which network ports and protocols their application uses to function so that you can properly configure firewalls.
Caution: Before creating the Allow All rule in Symantec Endpoint Protection Manager (SEPM), move the client into a client group by itself, with a non-shared policy. This ensures that the following test does not affect other computers. To move clients, right-click the client, then choose Move.
If this article does not resolve the issue, see Configuring firewall settings for mixed control for information on user interface control settings in the client.
For additional information on configuring firewall rules, see Managing firewall protection.