Is it necessary for a router, that inside and outside are on a different (sub-)net?
As an example: We have the following setup in the field:
- Network: 10.10.1.0/28
- R1: Router with R1.outside access to internet
- R1.inside: 10.10.1.1:
- R2: Router creatig VPN Tunnel to system on the internet
- R2.outside: 10.10.1.2 with 10.10.1.1 as default gw
- R2.inside: 10.10.1.3
- C: Ethernet capable controller
- 10.10.1.4 with 10.10.1.4 (R2.inside) as default gw
- All those interfaces are plugged into one switch (except R1.outside, which usually is a GPRS connection)
^ | | +---------+-------+ | Outside | | | | R1 | | | | Inside | +-------+---------+ | | | | +-------------------------------------------+ | | | | Switch + + + + | | | | | | +-------------------------------------------+ | | | | | | | | | +---------+--------+ | +-------+-------+ | Outside | | | | | | | | | | R2 | | | C1 | | | | | | | Inside | | | | +---------+--------+ | +---------------+ | | +-----------+
The question in more detail:
- by definition: Is there anything in the definition of a "router" that would disallow that setup? (Could not find anything in rfc1812 but I may have overlooked it)
- in practice: Is there any practical reason, common implementation details etc, that would make this setup wrong or seriously discouraged?
(Edit: To clarify: The topology is a given. It may be ugly. It may have implications. The question is: Is it wrong?)
