I stand at least partially corrected. Samba is running on gap, surprisingly. It’s not accessible from outside though, I was only able to connect from localhost.
I’d guess your Mac is either using FTP or DAV. What procedure do you use to mount your home directory? The only way I’ve ever mounted shares in OS X is using the Cmd-K/‘Connect to Server’ dialog, where you have to prefix the hostname with a protocol (eg, afp://, smb://, etc).