Yosemite application firewall?

[pctech]

Just out of interest as I've not had the opportunity to tinker with our Macs running Yosemite at work but does it come with some sort of application level firewall that has been beefed up recently?

I ask as one of the applications I support is made up of two components, one which acts as a server component and one which is a client that the user interacts with, they communicate using TCP/IP using the loopback address 127.0.0.1 of course.

Started to get reports of the client not being able to connect to the server all of a sudden.

There doesn't appear to be any sort of firewall software active on the customer machines.

Have had to hand the cases over to another department as don't have the opportunity to look into stuff as in depth as I used to be able to but would be interested to know from you guys and girls in the know.