This article tells which networking protocol Mac OS X Server uses.

The native networking protocol for Mac OS X Server is TCP/IP, based on the robust BSD TCP/IP stack used in much of the industry.

All the services in Mac OS X Server are tuned to deliver optimum performance over TCP/IP. AppleTalk is supported for some services for use with legacy clients, and to allow Macintosh systems to easily find the server. However, the server is not intended for use in AppleTalk-only networks, or to support large numbers of AppleTalk clients using Apple file services.