laforgue@imag.fr (Pierre LAFORGUE) (03/12/91)
Help please ! Does someone know a solution to my problem ?
Let be a Cisco router (AGS+) with various Ethernet connexions and a serial one
connected to a distant Cisco router (itself being on a distant IP network C).
Let be 2 local IP networks, whose IP address are respectively A and B.
Each Ethernet entry of the Cisco connects a subnet of A or a subnet of B,
excepting one which connects a distant network whose IP address is D.
I need to configure:
- for the network A a default route via a machine of C
- for the network B a default route via a machine of D
(all machine of A must communicate with the rest of the world via the
distant network C, all machine of B must communicate with the rest of the
world via the distant network D)
------------
---------- subnet A.1 ---------| |
---------- subnet A.2 ---------| |---......----- network C
---------- etc ---------| Cisco |
---------- subnet B.1 ---------| |---......----- network D
---------- subnet B.2 ---------| |
---------- etc ---------| |
------------
How could I do that ?
Is it possible to configure two default routes and to "play" with the access
lists to discreminate them ?
Thank you by advance.
--
Pierre LAFORGUE laforgue@imag.Frkwe@bu-it.bu.edu (Kent England) (03/13/91)
> From: laforgue@imag.fr (Pierre LAFORGUE) > Newsgroups: comp.dcom.sys.cisco > Date: 12 Mar 91 07:48:57 GMT > > I need to configure: > - for the network A a default route via a machine of C > - for the network B a default route via a machine of D > ... > ------------ > ---------- subnet A.1 ---------| | > ---------- subnet A.2 ---------| |---......----- network C > ---------- etc ---------| Cisco | > ---------- subnet B.1 ---------| |---......----- network D > ---------- subnet B.2 ---------| | > ---------- etc ---------| | > ------------ > How could I do that ? What is usually done in your situation is to receive all route advertisements known to routers on nets C and D into the cisco (while sending nets A, B, and C or D) and send only a default to nets A and B. This creates a large routing table in the cisco which does not use a default route itself, while relieving the local nets A and B of having large tables by using a default pointing to the cisco. If you don't want the broadcast load on nets C and D, you may be able to use EGP between the cisco and the authoritative routers on nets C and D. You also need to decide whether the cisco can be a route between C and D. If so, then those nets need those route advertisements, like the cisco does. In this case, have the authoritative routers broadcast all known nets onto their nets C and D for the cisco and all hosts. Then no one on nets C and D uses default. --Kent