Today I was trying to connect to SQL Server from my OSx Mac and I was getting Unable to connect: Adaptive Server is unavailable or does not exist.

I was able to connect to another sql server in the same farm from laptop.

Found out by default –> TCP connectivity is disabled for SQL Server.

Microsoft SQL Server 2008 R2 > Configuration Tools > SQL Server Configuration Manager > SQL Server Network Configuration > Protocols for MSSQLSERVER

Protocol Name: TCP/IP (Enable)

Thats all :))