Mac OS X: Dial-up connection (PPP) fails to automatically disconnect

Sometimes Mac OS X may not seem to respect the automatic disconnect setting that is defined in System Preferences (which is 10 minutes of inactivity by default).

The reason is that unsolicited, inbound traffic from the Internet, usually caused by others' attempts to attack to your computer, can "tickle" the 10 minute timer, causing it to reset.

You can have your Mac ignore this unsolicited traffic by using Stealth mode. Follow these steps:

1. From the Apple menu, choose System Preferences.
2. Select the Sharing preference.
3. Click the Firewall tab.
4. Click the Advanced button.
5. Select the checkbox for Enable Stealth Mode.
6. Click OK.