Macbook pro sees other macs on the network intermittently

Hi folks,

I am running into some weirdness on my home network. I have three Macs: 2 Macbook Pro and 1 Mac Pro. The Mac Pro I am attempting to run headless using either of the MacBooks to manage remotely. The VNC screen sharing works OK, but the connection is intermittent. Most of the time, when I use Finder on the MacBook to connect to the Mac Pro via screen sharing, the Mac Pro is not listed. I then ssh to the pro via Terminal, and moments later the pro will show up in my MacBook's Finder and I can use the screen sharing (which, by the way, works fine but has annoying latency problems that I just don't see when I RDP in to my Windows box - another story).

The Mac Pro is running 10.6.8 (it's old) while the two MBPs are running Mavericks. The Mac Pro is on ethernet while the MBPs are wireless.

I'm afraid I don't know much about Finder's interpretation of networking, so I'm not sure how to troubleshoot this.

Any help or advice would be greatly appreciated.

Cheers,

Ron