Ok, thank you, that helps.
I have a site (A) which does not have local access to the internet. The site is connected via a private link to another site (B) that also does not have local access to the internet. Site A currently has the following route: 0/0 [OSPF/150] to an IP address on the router at site B. Site (B) has a route to 0/0 via interface ge-0/0/0.0 and an I.P. belonging to a neighbouring router (site C) with internet access.
How can I provide internet access to site A? Perhaps an OSPF policy is needed, but what exactly?