General • Address pool for SRC-NAT

Hey folks,

got a question regarding additional ip ranges assigned to a company that belong in a different subnet from the WAN IP address:

SCENARIO
1) WAN IP address = 10.10.10.2/30 (let's assume that this is a public IP)
2) Additional subnet assigned to the company = 10.20.20.0/29 (let's assume that this is a public IP)
3) Internal subnets with private IP addressing = 192.168.1.0/24, 192.168.2.0/24
4) a) 192.168.1.0/24 -> src-nat -> 10.10.10.2
b) 192.168.2.0/24 -> src-nat -> 10.20.20.0/29

QUESTIONS
1) Is there a problem if the additional subnet is not in the same subnet as the WAN IP address? I don't think so but I want to clear any doubts
2) Does the additional allocated subnet need to be configured on a specific interface on the router (physical (e.g., the wan interface) or logical (e.g., bridge)) or will writing source nat rules be enough (e.g., 192.168.2.2 -> src-nat -> 10.20.20.2)? I think that this is not a requirement on CISCO routers but I will lab this up in CML today to make sure.

I know that another option is to create an internal subnet with the additional range provided and assign public ip addresses directly on the devices but I'm specifically interested in how to handle the situation using nat.

Statistics: Posted by OptiTech — Tue Feb 27, 2024 12:25 pm

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