Can't connect Mac to Mac via Finder over LAN I'm having trouble getting one Mac on my home LAN to talk to another - let's call them Red and Blue. Red can't connect via Finder (under Shared) to Blue. But Red can open a Screen Sharing session to Blue. Blue can open a Screen Sharing session to Red, and connect to Red via Finder.
Both Red and Blue are using WiFi, connected to the same router. Both are running OSX Leopard, 10.5.8.

I have a third Mac I'll call Orange. Orange can connect via Screen Share or Finder to both Red and Blue.

What could be causing Red to have these issues connecting to Blue?
Lots of possible problems, from configuration issues on Blue to security filters in the router to other more obscure things.  Some more information will help pinpoint the problem.


Does Blue have File Sharing turned on?  If not, then that's the problem.
What happens when, on Red, using Finder->Go->Connect to Server... you try to connect to afp://Blue.local
What happens when, on Red, using Finder->Go->Connect to Server... you try to connect to smb://Blue.local
What version of OS X is Orange running?
Is Orange using a wired Ethernet connection to connect to the router or is it using WiFi as well?