X-lite configuration

Hi all,
I installed the x-lite softphone in my windows XP pc and configured as follows:
Display name: xxx
User name: xxx
Password: xxx
Authorization name: xxx
domain: nnn.nnn.n.nn
proxy address: nnn.nnn.n.nn:5060

where nnn.nnn.n.nn is the address of my linux box where I installed Asterisk.

I also installed the x-lite softphone in the same linux box where I installed Asterisk and configured it the same but instead of xxx, i used yyy

This is the sip.conf in the linux box:


The extensions.conf has the following section:
exten => xxx,1,Dial(SIP/xxx,r)
exten => yyy,1,Dial(SIP/yyy,r)

This is the problem:
If I call extension yyy from the phone installed in the linux box, it dials and calls itself (i’m able to answer on the second line)

If I call extension xxx (phone installed in Windows) from the yyy extension (phone installed in the linux box), it fails (call failed: 4004 not found).
The same happens when I called from the phone installed in Windows. In other words, I cannot make these two phones talk to each other.

if I enter in CLI the command “sip show peers”, it shows both extensions, xxx and yyy but the only one on-line is yyy (the one in the same linux box). somehow it does not see the one installed and running in windows.

Both Windows and Linux are running in my home network (bellsouth homenetworking DSL) and i’m able to ping both boxes so they see each other in the network.

Any help will be greatly appreciated. I’m very new to this an I’m struggling to understand how it works.