Troubleshooting Firewall Problems in Four Steps

By default, Windows 7 firewall blocks unrequested, unapproved incoming and outgoing traffic to reduce potential threats. At times, it may also block legitimate traffic if not properly configured and may cause applications’ problems. Connectivity issues may block applications outgoing communications when your Windows 7 machine is acting as a client or block incoming communications if your Windows 7 machine is sharing data such as, sharing folders to other clients. Other connectivity issues can happen when Windows firewall allows incoming traffic from the LAN or domain but blocks traffic from other networks.

The following four steps will help you isolated the problem:

  • If an application running on your computer fails to connect to a server but other users can (running the same application on their computers) then, the problem is within your client-side firewall configuration. This may be caused by a firewall rule that is blocking outgoing traffic for the application. Review and adjust outgoing firewall rules.
  • If the same application fails to connect to one particular host or server but connects to other hosts then the problem is from that particular server. A server-side firewall configuration problem may be solved by adding a firewall exception. If the problem is not resolved by adding a firewall exception on that particular server then it may be caused by a network firewall.
  • If you can connect to other hosts or resources only when your Windows 7 machine is connected to one type of network location such as, a home network then your client-side firewall is set with an exception configured for only one network location type. Add exceptions for different network location types to rectify the problem.
  • If you fail to connect to a server or resource while other clients on the same network can, and you have no firewall rules for outgoing traffic configured on your machine (you can temporarily turn off your machine’s firewall to verify this), then the problem lies within the server-side firewall configuration. This may be related to the configured scope of a server-side firewall exception. If adjusting the scope of the firewall exception does not solve the problem, then it may caused by a network firewall.