Problems sharing Internet connections, fixes

Several readers have reported an issue where they are unable to successfully share an Internet connection with other Macs. In many cases, the shared connection works properly for a few minutes, then suddenly drops.

MacFixIt reader Ben Miller writes:

"My problem is that when I share my Internet connection (in the latest case it is from a Verizon BroadbandAccess ExpressCard), other people can get Internet access through Airport Internet Sharing for a few minutes but then the connection abruptly goes down.  Other people remain associated to my AirPort Internet Sharing and they still have an IP address, but they have no connection to the Internet.  Usually if I stop Internet Sharing, disable/enable Airport and start Internet Sharing again they will regain access, but this poses a problem for me because I do long presentations for a living and I would like people to stay online while doing my full presentation.'

In some cases, this issue can be solved by going to the Network pane of System Preferences, clicking on "Port Configuration" and dragging the relevant sharing port ( Firewire, Ethernet) to the top of the list.

Also, note that if you have turned on the firewall on the Firewall pane of Sharing preferences, you also need to turn on Personal Web Sharing on the Services pane of Sharing preferences in order to share your Internet connection and allow computers connected to your Internet connection to browse the web. Although Personal Web Sharing is technically unrelated to Internet sharing, turning this service on opens the appropriate port (80) so that users sharing the connection can access Web sites.

An alternative to this is to open the "Sharing" pane of System Preferences, then the Firewall tab, and clicking "New" on the right-hand side. Then select "Other.." from the pull-down menu, and open the ports to which you would like to allow other users access. 80 for Web sharing, 443 for mail services, etc.

If you are experiencing a similar issue or have found success with a different workaround, please let us know.

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