How to send all outgoing traffic to GRE tunnel?

Question

Computer networks

Good day!
There are two networks located remotely from each other (two branches of the enterprise). Each network has many subnets. They must be merged using GRE. Then a problem arose: how to specify that all outgoing traffic would go into the tunnel? I would not want to do static routing, since in the future the network can expand, and static routing can be a minus in this case (I am doing term paper). Is it possible to somehow do this? If possible, how?

Answer 1

Well, in fact, not everything is clear with your description, but in the general case:
1. A static route is made to the external address of the GRE partner
like
add route ip.of.gre.partner ip.my.inernet.provider
2. The default route is prescribed to the internal address GRE
add route 0.0.0.0 0.0.0.0. ip.gre.other.side We understand
that without additional gestures there will be no Internet with such a scheme.
Probably it is necessary to lift dynamic routing (RIP, OSPF, EIGRP).

Answer 2

If you want to send exactly all traffic through the tunnel (so that one office goes online through another), then you need to register the route on the central router.
And if you need all the local networks of the second office to be accessible from the first office, and let's say Internet access was through a local router, then it's easiest for you to configure OSPF.
Need more information to answer.