How to prevent a single application from connecting to the internet?

[open0source]

Is there a way to prevent a single application from ever connecting to the internet? I have a program that always tries to update itself on startup, but the update breaks it. The preference to never check for updates isn't saved between each quit, and if it detects an update it will start downloading automatically, without my consent.

I've tried using the Security section in SysPrefs to block incoming connections, but that just leaves it stuck at 0% downloaded, instead of stopping the entire process. I'm stuck with disabling Airport, starting the application and getting past the main menu, and then re-enabling Airport, which is starting to become a pain.

Any help is greatly appreciated.

Edit: I'll use Little Snitch if necessary, but I only need to block the one application. If there's some kind of Terminal command or .plist file I could edit instead of spending $30 on Little Snitch, I'd like to take that route.

 

[McGiord]

Use Little Snitch. Google it.

 

[MacDawg]

I think Little Snitch does this... but I have never used it myself

Woof, Woof - Dawg

 

[gr8tfly]

I haven't set it up, myself, but you can set the built-in Leopard firewall to allow access for only certain services and applications. It might be a bit clumsy to set it up to block, rather than allow, but it looks like you can use it that way.

 

[angelwatt]

You can try using one of the built-in firewalls. Go to System Preferences > Security > Firewall. Choose the radio button for "Set access for specific services and applications. Then hit the + button at the bottom and find the application in question. Once it's in the list highlight it and click on the drop box on the right and choose "Block incoming connections." That should do it in theory.

 

[Jethryn Freyman]

I use Little Snitch.

 

[tmiranda]

You can try using one of the built-in firewalls. Go to System Preferences > Security > Firewall. Choose the radio button for "Set access for specific services and applications. Then hit the + button at the bottom and find the application in question. Once it's in the list highlight it and click on the drop box on the right and choose "Block incoming connections." That should do it in theory.

you dismissed your own answer...the OP wanted to block an application from going out to the internet, not in. Leopards built-in firewall only allows you to block incoming traffic to applications, not outgoing. Use littlesnitch or netbarrier.

 

[madog]

Another vote for Little Snitch. One of my necessary apps that I was more than happy to purchase.

 

[eleven7]

What app is it you're trying to block? I tried little snitch but found it really annoying so go rid of it. Depending on what app, you could try modifying your hosts file in your "/etc" folder?