Which firewall is the best for Windows Server 2012?

Fortigate is the best practice solution and it's Hardware Firewall  Good luck and if you need more information about it you can find here all information with this link                                                       

http://www.fortinet.com/products/fortigate/

Dell Sonicwall TZ series< + Kaspersky End point security for business

So much of this depends on your organization and both internal and external needs and requirement. As a general rule you get what you pay for. Cisco, including the Meraki line, are very good all around choices. I'd stay away from Sonicwall since they were acquired by Dell a few years ago.

Fortigate is the best solution

There are many hardware firewall like sonicwall etc.

agree with all expert answers above

If you say, "Which Firewall is best for Windows 2012?" --- it means you are individually thinking abou the protection of 2012 server.

Here is my answer:

1. Usually hardware firewalls are used for network security, not only for a single machine/server. such as: ASA, Sonicwall, ProSafe, Juniper, FortiNet, etc.

2. If you only think about your Windows 2012 server, you can check Windows Firewall which is default in Windows 2012 server. You also can use script and power shell to enhance its power. This is called software firewall. You can check a list of software firewall here: https://en.wikipedia.org/wiki/Comparison_of_firewalls

Please note that antivirus and firewall are different. if you think about antivirus you may go and compare with many products :

https://en.wikipedia.org/wiki/Comparison_of_antivirus_software

Hope this clearly gives you answer.

Since you're asking about FW for Windows Server 2012 OS, the best is to use its built-in firewall. However at enterprise level for centralized control I've used McAfee with a lot of features which is centrally controlled by McAfee ePO Server. I think that is best to use. There are other competitors as well like Symantec Endpoint Protection and Kaspersky AV etc. For enterprise network firewalls, Gartner's 2015 Magic Quadrant states Checkpoint and Palo Alto as leaders while Cisco and Fortinet as top challengers. Check their report here: http://www.bradreese.com/blog/5-28-2015.pdf

I agree with other answers. But, It depends on your requirement. What is your basic requirement, how many users will configure in firewall, which feature do you need in firewall (i.e. policies, reporting logs, graphical interface, etc.). Currently there are many brands which provides firewall, but we need that brand which make his product up to date. Because firewall need updation according to new security challenges occurs in cyber world.

Personally I suggest fortigate, because I am comfortable with it. Other than that Cisco, Sonic wall, and best one is checkpoint. These are the brands with different price range.  

Windows Server too have a firewall inbuilt, and mostly of the antiviruses have also inbuilt firewall. If you want to use a professional firewall then go for fortigate.

forinet and Paolo Alto are best UTM in the market