kubuntu 7.04 and vpn

[jack]

I have Kubuntu 7.04 up and running, and have just gone through this link
to setup a vpn client:
http://pptpclient.sourceforge.net/howto-debian.phtml#install

When I run pon <vpn_name> , and then run plog , it shows as being
connected.  What I'm not sure of is how to actually tell that I'm really
'in' ... I tried to ssh to one of the systems that I have access to, but
it times out.  I also tried setting up a network connection via
konqueror, but it also timed out.  Trying to establish a samba
connection created other problems that I don't think are relevant to
this (complaints about having iptables running and such).

So, my question is - once I'm apparently connected to a vpn, then what?
(sorry for the n00b query, but it is the first time I've ever used
vpn...