Caution

Although many administrators are tempted to disable the Windows Firewall, it is certainly worth leaving it in place with the necessary rules configured. If you are convinced you don’t want to use the Windows Firewall, and you don’t plan to use a third-party operating system layer firewall, leave the Windows Firewall service running, but configure the rules to allow all traffic to pass unhindered. This prevents possible problems in interacting with the Windows Filtering Platform.

Tip

If Windows Firewall was off during the first installation, you can simply turn on Windows Firewall and run the Lync Server Deployment Wizard to configure Lync Server 2013 Windows Firewall Rules.