Understanding two NICs requirement for SQL fail over cluster I am trying to make an SQL Server 2012 failover cluster. I have two DB machines. I understand that both machines need 2 NICs each. In my organization the IP scheme assigned is something like 192.168.1.X.

So I want to know if I assign 1 IP to each NIC, will that be enough? Like assigning 192.168.1.50, 192.168.1.51, 192.168.1.52 and 192.168.1.53?

Or two of the NICs in each machine have to have some private network scheme which will allow them to communicate directly?
First, there's no SQL Server 2013, but the good news is that the version number of SQL Server doesn't matter. It's more based on Windows failover cluster networking, which is explained here in a 3-part series by the Microsoft folks:

http://blogs.technet.com/b/askcore/archive/2010/02/12/windows-server-2008-failover-clusters-networking-part-1.aspx

And then additional info in part 4:

http://blogs.technet.com/b/askcore/archive/2010/04/15/windows-server-2008-failover-clusters-networking-part-4.aspx

Short story - you need some network redundancy, but you don't have to get it with multiple IP addresses. Instead, you get it with network teaming software.