Messenger audio

Archived from groups: microsoft.public.windowsxp.messenger (More info?)

I have two computers:
Computer A is connected directly to the internet broadband
Computer B is connected via Computer A using two network cards and a cable,
and then onto the internet.

I can use audio in messgenger from computer A, but it doesn't work from
computer B. It just keeps saying the convesation has ended when you try to
connect.
There is obvisouly something wrong with the internet sharing on Computer A
Computer B messenger reports its connect as "You are connected to the
internet through a UPnP IP restricted NAT. (Administrator)"
I have no idea what the restricted NAT means or how to change it, but I
guess that could be a problem.

I can see a web cam between the two computers.
Computer A has Norton Internet Firewall, but I have disabled it and it makes
no difference.

Please has anyone got any ideas?

Thanks

Both computers using Lastest Messenger 6.2, both using XP