Presumably you are asking if XP Home can connect to an SBS2003 domain by
VPN, and the answer is yes. I have made little use of VPN from home for a
couple of years now, but when I used it often, I normally did so from a
Linux computer, which was certainly not a domain member. I have also
used XP Home.
It may not be a joyful experience, as it seems to me that a domain
member computer never has problems accessing network resources,
something which can be a bit hit-or-miss for an unjoined one. You'll
also need to enter account details more than once. But it should connect
without difficulty. It is possible to join an XP Pro machine to a domain
over VPN, so it must be able to connect initially as a non-member.
So treat this as a normal 'VPN does not work' troubleshooting exercise.
Have a look in the System Event log on the server at the appropriate
time, to see if the server accepted the TCP/1723 connection but did not
get the follow-up protocol 47 (GRE) messages. That's generally the
reason why the client says 'connected OK', but authentication does not
happen. The authentication negotiation is the first data passed through
the GRE tunnel.
If that is the case, then look for something different about the route to
the server. You do not say whether the netbook is using the same Internet
connection as the domain members you mention earlier. If it is, then
it is something about the netbook itself that is the problem, probably
the firewall. The built-in XP firewall should not need any configuration
to be a VPN client, but a third-party firewall will.
Also, if you are trying this from the same location, only one PPTP VPN
at a time can be made between two IP addresses. If a VPN is already open
between the client and server addresses, then no further connection can
be made through the same route.
If you are trying to connect through a public wifi system, something a
netbook may well be used for, remember that many if not all will filter
the connection, limiting it to common protocols. A well-known pub chain
in the UK has free wifi access, but passes neither SSH nor OpenVPN. I
have not tried it with PPTP VPN, but I doubt whether that will work
either. Quite a few business-type hotels have heard about VPN, and allow
TCP/1723 through, but some are clearly unaware that they also need to
pass GRE.
--
Joe