First, a little back story on network ports. Network ports are a kind of virtual port that different types of data travel through. The data that passes through your firewall is assigned to a specific port, and each port has a unique number. For example, Web-based data, like the information that tells your Web browser how to display the sites you visit travels on port 80. Port 25 is commonly used for email.
If your firewall is blocking a specific port you need, any information traveling through that port will be blocked. Keeping with our Web data example, if port 80 is blocked, you wonit be able to view Web pages.
Now back to our regularly scheduled Quick Tip. When your Macis firewall is active, many applications that need to send data on a closed port will either ask you to manually open the port, or will open the port for you. If you need to manually open a port, hereis what to do:
Start by finding out which port you need to open. If an application asks you to manually open a firewall port, it should also give you the associated number. If not, check the applicationis documentation, or for the ambitious, you can check the IANA port number Web page. Once you have the port number, itis time to modify your firewall settings. For this example, weill assume that FileMaker Pro needs port 5003 open.
- Launch System Preferences. You can find it by selecting Apple menu > System Preferences.
- Click the Sharing.
- Click the Firewall tab.
- Click the New button in the Firewall pane.
 Click the New button to create a network port. |
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