alpa

Very strange problem

I have duo connected to web via fiber glass, everything is working fine.
friend of mine has uno connected to web via fiber glass, everything is working fine.

We are using the same ISP, the problem is that we cannot see eachother.
duo has ip address xx.xx.197.xx
uno has ip address xx.xx.204.xx
when try to ping they cannot ping each other, after ping if we put check arp tables (arp -a) we get following on uno:
? (xx.xx.197.xx) at <incomplete> on eth0

and following on Duo:
? (xx.xx.204.xx) at <incomplete> on eth0

I also have AP with another ip address (xx.xx.197.xx) friend also has AP with another ip address (xx.xx.204.xx) , and they can see and ping eachother without any problem.

Only vu boxes when conected directly to fiber glass cannot see eachother and after trying to connect we get incomplete error.

btw both boxes are working excelent and conect and can be connected to outside ISP IPs without any problem.