08-29-2011, 06:32 AM

Hi

I know Mac's are largely safe from virus's but do I need to get a firewall? Does my Mac come with one?

If I do need one, what is recommended? Any free apps for it? :-)

I am running Lion on an early 2009 Mac Mini and also have Lion on a 2007 MBP

08-29-2011, 06:39 AM

Comes with one. Go to system prefs -> security and you can turn it on.

08-29-2011, 06:40 AM

Top 3 hits from a search for "firewall".


Official antivirus, malware, and firewall FAQ

Does Lion come with Firewall?

firewall question

08-29-2011, 12:07 PM

Thank AOIFEEE and BOBTOMAY very help thank you! :-)

08-29-2011, 08:07 PM

Bottom line: it's turned off by default for a reason, and that reason is that your router (if you have one) almost certainly has a far superior hardware firewall already active. Two firewalls do not make double protection, they make double the chance of conflicts. Unless you have a specific reason to turn the Mac firewall ON, leave it OFF.

08-30-2011, 08:17 AM

Chas - thank you! Very helpful!

08-30-2011, 11:25 AM

Originally Posted by chas_m

Bottom line: it's turned off by default for a reason, and that reason is that your router (if you have one) almost certainly has

Bottom line, it's included for a reason, and that reason is that laptop owners (especially) often use public wi-fi networks.

a far superior hardware firewall already active.

For most things, the OS X application-based firewall is superior to the NAT function of a router.

Two firewalls do not make double protection, they make double the chance of conflicts. Unless you have a specific reason to turn the Mac firewall ON, leave it OFF.

The default configuration is pretty well thought out and won't cause any problems with common Mac software, including Apple's included services. (If you're running a server or a third-party remote access service, you might need to do some work to get it set up, but if so, you're probably up to the challenge.)

Unless you have a problem with it, leave it ON. You probably won't ever notice it's there.

08-30-2011, 02:23 PM

+1. As technologist states - it's there for a reason. I don't agree with the mindset of "turn it off, you don't need it". And, I don't believe it's prudent to advise new users to do so.

08-31-2011, 07:28 AM

Originally Posted by technologist

Bottom line, it's included for a reason, and that reason is that laptop owners (especially) often use public wi-fi networks.

This is, I admit, purely anecdotal ... but I checked with all 17 of the public places I use Wi-Fi (asked politely to see their router) and guess what -- every single one of them has a hardware firewall already. Unsurprising these days, really.

There's a LOT of misunderstanding of what a firewall does and does NOT do. It does NOT magically protect you from ... well, much of anything more than a DDOS attack, which would also affect every other user of the Wi-Fi network. Thus, most places that offer it already have a firewall in place.

(If you're running a server or a third-party remote access service, you might need to do some work to get it set up, but if so, you're probably up to the challenge.)

This part I agree with.

08-31-2011, 10:54 AM

Originally Posted by chas_m

This is, I admit, purely anecdotal ... but I checked with all 17 of the public places I use Wi-Fi (asked politely to see their router) and guess what -- every single one of them has a hardware firewall already.

Of course they do. But everyone else on that network is behind the firewall, and you're exposed to all of them.

The sweet looking girl at the next table over in your local Starbucks may not be out to get you, but her zombified Dell may well be.

And yes, there is a lot of misunderstanding about what a firewall does. And DDoS attacks are not what a firewall protects you against (some do, but that's not what the OS X firewall does.) Firewalls prevent outsiders from connecting to services on your computer. Not planning to run any network services? Great! Using the firewall won't affect you at all; you'll never even know it's there. Set it and forget it.

08-31-2011, 10:58 AM

i have been using both and noticed no difference in what I do but gives me piece of mind when I am away from home also the fact last week forgot to turn in back off when I got home so I left it on still did not notice any difference. So for me on it is.

08-31-2011, 01:48 PM

Technologist is spot on !
Turn the OS X firewall on and forget about it.... roam the internet with peace of mind.

Cheers ... McBie

08-31-2011, 02:03 PM

Just for clarification, a firewall doesn't protect you from the most common form of data piracy - namely packet sniffing. A firewall is comparable to locking the doors and windows on your home, to prevent unauthorized entry. However, if you stand at your front door and yell to your neighbor across the street, there's nothing to prevent your next door neighbor from hearing the conversation. Same with the coffee shop - your wireless signal, if not encrypted, is being "shouted" across the room, and anyone with a mind to can capture that information in plain text. That's why firewalls are good, but they're only one piece of the security puzzle. Ideally, every coffee shop would have a password protected network, with suitable encryption. More and more are moving that way, but it's by no means universal. Be careful with passwords, only access sites with sensitive information on networks you know to be secure, and consider setting up a VPN with your office or home for better security.

08-31-2011, 02:40 PM

Technologist is DEAD on. It does not hurt at all to run the OSX firewall, especially if you are out and about. I don't care if the Hot Spot's router uses even SPI, that is only for the WAN, not the LAN. Anyone in the area on the LAN is still open to every other system on that LAN.

People can argue this all they want, but I have seen it proven over and over. Some routers only have NAT. A true HardWare firewall uses at least SPI (Stateful Packet Inspection) or even better Deep Packet Inspection (DPI). Any decent Firewall that does not at least have SPI, I will not even bother with. So far only very expensive Firewall appliances have DPI though.

Any doubters out there come here and check my SPI Firewall logs and see exactly what it's blocking. And yes, I have a Firewall appliance. Works great! Picked it up at a Thrift Store for $5. It's worth close to $1000!

09-01-2011, 10:33 AM

Wow! This got a lot more exciting since I came on last!

Bit confused now but I think best practice is leaving it on! Thanks all! :-)