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(1) 5

Lightweight and fast application firewall.   Free
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TCPBlock is a lightweight and fast application firewall for OS X 10.6 or later developed by The OS X firewall protects you from connections that come from outside of your computer. But what about the software from your computer that opens new connections to the internet? With TCPBlock you can prevent selected applications on your computer from opening connections to the network.

TCPBlock is implemented as a loadable kernel module which contains all the blocking logic. You can configure it in the System Preferences TCPBlock preference pane or with the
What's New
Version 4.0:
  • Cryptographical hash filtering.
  • Optionally block incoming connections too.
  • Support for OS X 10.5 removed.
Intel, OS X 10.6 or later

MacUpdate - TCPBlock

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TCPBlock User Discussion (Write a Review)
ver. 4.x:
Your rating: Now say why...

sort: smiles | time


Michiel Brand reviewed on 27 Jan 2014
Used to be very good, but since Mavericks it keeps on crashing - whether I install the stable or experimental version, no difference. Keeps on asking for sending crash reports, which is a bit irritating, please fix asap, thx
[Version 3.0]

1 Reply

Delantis (developer) replied on 28 Jan 2014
Please send more details and especially crash log files to the contact email address on my website.


Kobalt reviewed on 15 Jan 2014
Yes, I use LittleSnitch but feel much better for using TCPBlock at the same time. Excellent app.
[Version 3.0]



Mac Os X 4ever reviewed on 09 Jan 2014
I just donated. This software just keeps getting better and better every beta, and so far most of the requests for features that I have made have been added.
I see no reason to even think about going back to Little Snitch.
LS just keeps robbing people blind with their insanely expensive upgrade fees when they fix bugs, and TCPBlock seems to be doing a better job. It's more powerful and reliable.
Thank you for great software.
[Version 3.0b7]


Mac Os X 4ever commented on 04 Dec 2013
It's getting better, but something that was missed is the notifications.
It can blast out hundreds of connection notifications constantly because there doesn't seem to be a way to customize it.
It should only show the blocked connections, not the ones that are white-listed.
That should be optional at the very least, otherwise it just goes all the time.
I had to shut off the alerts in notification Center because of this.
If it only showed the blocked apps, then it would be useful information, then I could choose to white-list them as I am notified.
It is getting much better though.
I like it a lot, and I am waiting to see the next beta. hopefully this issue will make it into the next beta.
Keep up the good work.
I could see it eventually replacing little snitch and others if it ever evolves to blocking specific addresses to each app, but if it never ends up that way, it is still very useful.
[Version 3.0b4]

3 Replies


Mac Os X 4ever replied on 04 Dec 2013
I just found it. It will do what I was asking, it's just strange because it's not in the preferences where it should be, so I didn't see it.
You can change the notifications from a menu item that it adds to your menu bar.
This seems a strange way of doing it. The options should be in the application settings like every other mac app that exists.
I have enough in my menu bar, but at least it's working well.
Hopefully by the next beta this can be resolved.
There's no reason that I can see to have an extra menu bar icon just for a few preferences that should be in the applications settings page, unless they plan to add more functionality to it later.
At first I thought it would be a good idea to allow and disallow the currently running application by checking the "authorized" option as I have an app forward, but that's not how it works. Authorized seems to stay checked no matter what access the forward running app has.
It is much better than the last version. Thank you for adding the functionality.
Delantis (developer) replied on 05 Dec 2013
Only applications can post alerts and messages to the Notification Center. The TCPBlock pref pane is not allowed to do so because it is not an app but a bundle running inside of System Preferences. This is how TCPBlockNotify was born, which is in deed an OS X application with its own set of preferences. Instead of running it with the full menu, dock icon and so on, I opted for the less intrusive alternative to display it as a menu bar item. The notifier’s preferences are set directly from its menu bar item where you can access it very convenient: Just two clicks are needed in order to turn unwanted notifications on or off.
Authorized means: The notifier is authorized to modify your app list, which is a privileged operation. Therefore it asks you for credentials. It will stay authorized until you uncheck it. If you click a TCPBlock notification in the Notification Center the notifier asks you if you want to add or remove the affected app from your Application List.

Mac Os X 4ever replied on 11 Dec 2013
Thank you Delantis. I hate the way I can't reply to you in MacUpdate. I can only reply to the original post.
I like the new version a lot and have another suggestion; an ignore list.
Google has the worst spyware/virus on the Mac. they have a app that constantly changes locations and reloads itself (virus), so there's no way to delete it.
My notification center is filled with block notices from the same app over and over.
Can you add a way to have an ignore list?
My notification center is filled all the way with nothing but blocks from ksfetch.
I am displaying the max number of notifications, but there are so many of these that it still fills the entire thing up.


Kobalt reviewed on 17 Nov 2013
Just a bit worried about the disclaimer on Jo's website: 'This is a beta version, things may not work as expected.', but I'll give it a go.

My star rating is for the stable v2.1 and may well increase once v3 is out of beta, because it seems to tick all the missing boxes.
[Version 3.0b1]


Mac Os X 4ever commented on 01 Aug 2013
I really like this program, but I wish it would get updated soon to take care of very annoying problems.
1) Even if I leave the config window open to monitor and keep whitelisting apps, the damn thing locks constantly and I have to constantly enter my password. This is FRUSTRATING to say the least. It shouldn't lock until I close the config window.
2) It would be really nice to have a popup window feature to whitelist apps the 1st time they try to get out.

Other than this, it is a really nice program and I am continuing to look at it as a possible permanent replacement for Little Snitch.

I just hope there are updates soon, I hope it's not a dead program. It is really nice and I would to see it continue.
[Version 2.10]

4 Replies


Mac Os X 4ever replied on 01 Aug 2013
Also would be nice to right-click and do a reveal in Finder, Man lookup, and internet search. This would help ti ID processes that we need more info on.

Brilormac replied on 13 Sep 2013
"I just hope there are updates soon, I hope it's not a dead program. It is really nice and I would to see it continue"

Did you pay the $10 donationware to the developer? Many tools like this languish due to lack of money.

Mac Os X 4ever replied on 09 Oct 2013
No, didn't donate yet. I have paid too much money over the years to just have the app dead-end, go out of business, etc.
It's very frustrating.
I paid for LittleSnitch, and now that's a waste too.
If this thing evolves and I see these features being added, then once I know it's not going away, and development is continuing, users suggestions are being added, etc, then I can see donating.
There are so many apps I have paid for that are long gone.
There haven't been any updates on this for a long time.
I just have to wait and see.
I do hope the suggestions listed here are listened to and it continues. It's a great app with a great start, but then again, I have put my money into many "great starts" before, and I would have been better off flushing it down the toilet.
Only time will tell...
JoD5782 replied on 17 Nov 2013
Checkout the new 3.0 beta at the developer's site.

Afcgbbob commented on 22 Jul 2013
For once I will be short (impossible). How is it you say Free but put in parenthesis $10? I find that rather confusing. You see I said I was short.

BTW does anyone know of any Mags looking for an Android reviewer? T-Mobile gave me a myTouch Q for free and like the Mac I work it and organize it like a Mac. I even found a way to multitask on it.

[Version 2.10]

1 Reply


MacUpdate-Nick replied on 22 Jul 2013
Sorry for the confusion; TCPBlock is donation-ware. We've updated the listing with a note to reflect this.


WesJT2006 reviewed on 07 Feb 2013
TCPBlock doesn't appear to fully work. I've been using it a couple of months and it seemed to be working fine at first. It would prevent applications from connecting to the internet unless I had them whitelisted, which is how I had it configured. But the other day I was using uTorrent to download several files (a total of 7 or 8 GB). The files completed downloading, but then I remembered that I never whitelisted uTorrent (or anything other the Google Chrome for that matter). To test this out I added a new torrent and it began downloading with no problems, but TCPBlock stated that it was blocking uTorrent from connecting. If TCPBlock tells me that the application is being blocked, yet the application is clearly sending and receiving large amounts data, then TCPBlock really can't be trusted. This really makes me wonder what other connections are being allowed without my knowledge.
[Version 2.10]

4 Replies


Mikael B replied on 19 Feb 2013
Thanks for the warning. What OS X version? The behavior may be different in different versions.

WesJT2006 replied on 23 Feb 2013

Negritude replied on 02 May 2013
What did the log say? Under "Connecting Apps", when you were running uTorrent, was uTorrent listed as being allowed to connect out? Was there anything else in the log that you didn't recognize?

The system name or the name of a subroutine that is used to connect out may be different than the name of the application itself. With TCPblock, you have to enter the EXACT name or it won't work.
Delantis (developer) replied on 04 Dec 2013
This is so due to a bug in v2.10 related to the filtering of UDP connections. Thanks to your comment I have solved the bug in the actual version 3.0b4. If you block a running uTorrent then the current download streams are not killed but it can not open new downloads. At the next start of uTorrent no downloads are possible anymore.


zaydon reviewed on 27 Dec 2012
Great lightweight outbound firewall. It doesn't learn like some other products, but it works well if you instruct it with the apps you want to block.
The great thing is the value and the limited resources this application takes.
Its very simple with few options per se. If you go to the developers website you can learn how to setup blocking notifications in notification center in mountain lion.
[Version 2.10]


Anthony1947 commented on 25 Dec 2012
Not sure to make this a Comment or a Troubleshooting issue — but, I suspect that Troubleshooting issues get less attention.

I've had issues with FaceTime — flat out would NOT work. I tried every possible solution, finally got help from the Apple TechSupport folks. It turns out that TCPBlock was the culprit — I had to remove it to get FT functionality again.

I really counted on TCPBlock to act as my application firewall — too many apps 'phone home' or wherever for my liking.

I hope that something can be done to enable me to re-install TCPBlock so that I can have its protective functionality.

Many thanks to the developers for this excellent software.


Two 2011 iMac's— 10.7.4/10.7.5
[Version 2.10]

WaynesWorld had trouble on 28 Dec 2012
Unable to get the White List functionality to work. Select "White List", then Add (+) app. Then "Select Application" and add "Safari" as a test. Close the dialog, start up Safari and won't connect to anything. Re-Open TCPBlock and either disable or uncheck "White List" and remove Safari and try to connect again using Safari and it works. It's a mystery as I can't seem to find reference to anyone else having this problem

[Version 2.10]


Dorkypants had trouble on 26 Sep 2011
2 problems:

1) Whitelist sometimes doesn't stick: i.e., items I add to the Application List disappear from the list after a reboot. This has happened for Unix daemon programs rather than GUI apps.

2) On wake, I've gotten a Growl notification that a daemon has been blocked, but when I open the prefpane, it's not on the list of Connecting Apps so that it can be added to the whitelist.
[Version 2.9]

2 Replies

Delantis (developer) replied on 29 Sep 2011
1) Can you reproduce the error? And if so can you please write me the steps to reproduce it?

2) This is so because at the time the notification was sent the prefpane was not open. The Connecting Apps tab maintains no backlog of connections. You can see just the network activity from the time on you open it.

Dorkypants replied on 29 Sep 2011

2) Yes, I figured out the prefpane needs to be open and set up my login to do so.

1) Hasn't happened again. If it does, I will send details.

-TiTAN- rated on 23 Mar 2014

[Version 4.0b1]

fawza rated on 26 Feb 2014

[Version 3.0]


BadBadger rated on 16 Jan 2014

[Version 3.0]

-TiTAN- rated on 16 Jan 2014

[Version 3.0]

dutkutug rated on 13 Jan 2014

[Version 3.0b7]

Voongoto rated on 01 Mar 2013

[Version 2.10]

MercuryNu rated on 14 Aug 2011

[Version 2.8]


Zuulito rated on 02 Dec 2010

[Version 2.7]

Version Downloads:771
Type:Utilities : Network
Date:12 Apr 2014
Platform:Intel 64 / Intel 32 / OS X
Overall (Version 4.x):
Ease of Use:
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TCPBlock is a lightweight and fast application firewall for OS X 10.6 or later developed by The OS X firewall protects you from connections that come from outside of your computer. But what about the software from your computer that opens new connections to the internet? With TCPBlock you can prevent selected applications on your computer from opening connections to the network.

TCPBlock is implemented as a loadable kernel module which contains all the blocking logic. You can configure it in the System Preferences TCPBlock preference pane or with the tcpblock command line utility. All the configuration changes are made persistent in a configuration file on the hard disk. At system boot time the TCPBlock kernel extension reads its configuration from disk and is ready to go.

Note: TCPBlock is free to download, but $10 donations are gladly accepted.

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