macrumors 6502a
Original poster
Feb 18, 2010

I use my MBP 13" for browsing and FTP using wifi/3g broadband. I saw the firewall was turned off after reinstalling Lion so I turned it on. Is there a danger if it is off? I had it off for a week.

Also, which should I check:

block all incoming connections
automatically allow signed software to receive incoming connections
enable stealth mode

i am having some ftp transmission issues with my broadband 3g card. don't know if this is related to turning firewall on and clicking "automatically allow signed software.." and "enable stealth mode."

Please help.



macrumors regular
Aug 4, 2011
Just turn it on with the "invisible mode" checked. Don't know how you spell it in English. It's the very bottom checkbox in the firewall preferences.


Moderator emeritus
Sep 8, 2010
Is your MBP behind a hardware firewall, such as an Airport Extreme base Station or other router? If so, technically speaking you don't have to enable your OS X software firewall. It doesn't hurt to either.

If you block all incoming connections, you may have to add some exceptions to the rule in the box below the option so that certain programs that you want to work, will; including network file sharing amongst computers you own, AirPlay, the Remote App for iOS to control iTune on your MBP, etc...

Stealth mode makes the computer appear invisible on the Internet and LAN and will not respond to port queries with an "open" or "closed" status, instead it acts as a black hole to the ping request and the requester never gets an answer back.

Because I have an AEBS covering my iMac, I don't have all the features enabled in my OS X firewall.

Screen Shot 2011-09-02 at 4.06.52 PM.png

If I weren't behind the AEBS or other hardware firewall, I would be enabling ALL of the security features of the OS X software firewall.


macrumors 6502a
Original poster
Feb 18, 2010
Hi, I have little snitch running. I just had to uncheck "Block all incoming connections" and add the Omnifocus app to bypass the firewall so I can sync my to do list with my iPhone 4s.

I checked "Automatically allowed signed software to receive incoming connections" and "enable stealth mode". Is this safe? I had previously blocked all incoming connections on 10.7.2


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