Can't connect remotely to SQL Server 2014 on Windows Server 2012 R2

Question

I am trying to install SQL Server 2014 on Windows Server 2012 R2. I can connect locally using windows authentication and sql server authentication, but when I try to connect remotely using hostname\instance, I get error:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) (.Net SqlClient Data Provider)

In SQL Server Network Configuration I have shared memory and tcp/ip enabled and named pipes disabled.

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Under TCP/IP Protocol, I have Enabled=Yes, Keep Alive=30000, and Listen All=Yes

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Under IP Addresses, I have

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The Windows Firewall is turned off (for now). The machines are not part of a domain just p2p workgroup.

The client machine is XP SP3 pro. I tried connecting using SMSS and odbc, but both failed.

Don't know if it is relevant, but I ran sp_readerrorlog on the server and I saw this in the logs

The SQL Server Network Interface library could not register the Service Principal Name (SPN) [ MSSQLSvc/SERVER_2012:49184 ] for the SQL Server service. Windows return code: 0xffffffff, state: 63. Failure to register a SPN might cause integrated authentication to use NTLM instead of Kerberos. This is an informational message. Further action is only required if Kerberos authentication is required by authentication policies and if the SPN has not been manually registered.

Sql Browser is enabled and running.

Allow remote connections to this server is checked.

Answer 1

Turns out it was the firewall. I had only disabled the firewall for domain not for private network.