Quoting Lee Sharp <leesharp at hal dash pc dot org>:

> From: "M0n0wall" <m0n0wall at toyne dot cix dot co dot uk>
>
>> I'm not sure if this is related, but I have just been playing with 
>> two wifi connected PCs and noticed that they cannot talk to each 
>> other. I can quite happily ping m0n0 from either, but not each 
>> other. The wifi router is effectively being used to pass traffic 
>> directly to m0n0.
>
> On this you probably have access point isolation enabled on your AP.  
> It "supposedly" adds security by not letting clients see each other, 
> but in practice it just makes things harder.
>

Thank you for that. Looks like my best option is for all PCs to VPN 
into the main network first - just need to work out why the connection 
isn't completing.

Kevin