VNC: vncviewer no route to host on same lan

[Richard Emberson]

I've got two Fedora bozes (A & B) on the same lan (connected through a 
netgear switch).
They can ping each other and ssh bach and forth. There is a firewall 
between the
lan and the internet (the firewall is NOT between the two machines).

On machine A, I've got a vncserver running. On machine A, I can run the 
command
 > vncviewer A:1
successfully; self vnc-ing works.

On machine B, when I run the command
 > vncviewer A:1
I get

main:   unable to connect to host: No route to host (113)

what wrong?

Running 'netstat -l' on machine A, yields (plus other stuff):
tcp        0      0 *:vnc                       
*:*                         LISTEN     

In /etc/services I've got:
vnc             5950/tcp                        # 1010x740 vnc
vncs            5951/tcp                        # 800x600  vnc

Doing a 'ps auxwww | grep Xvnc' yields:

Xvnc :1 -desktop roxanne:1 (myuser) -httpd /usr/share/vnc/classes -auth
/home/myuser/.Xauthority -geometry 1024x768 -depth 16 -rfbwait 30000 
-rfbauth
/home/myuser/.vnc/passwd -rfbport 5901 -pn

Googling provided no help.

Richard