login without actually log in

hello there,

I have a little problem I hope you could help me with
Because of the proxy at my work, I can't use the php POST method on a forum using punbb (using firefox). Meaning I can't submit a form, be it log in or posting.

I'm mainly looking for a way to log in to a punbb without using the POST method.

I have 2 ideas :
- is this possible to login via url ? I know some forums where you could put in url something along the lines of :

www.xxxxx.com/forum.php?login=xxxx&password=xxxx

. Is there a way to do so with punbb ?
- other idea would be using cookies : could it work that i login at my home then transfer the cookie at my work and then I would auto-login ?

If someone has an idea please tell !

Regards