Use a range from an ISP on an MX WAN interface which isnt in the same subnet
We have a Meraki MX and an ASA, currently the ASA is happy with running the sets of public addressing (we can use both on the ASA) our ISP has issued.
The ISP has issued the below on a single access circuit (this is the secondary circuit, we already have a working circuit/range in WAN1 which is different) this is exactly how the ISP describes the public subnets we can use on this circuit.
WAN Pool:- 184.108.40.206/29
LAN Pool :- 220.127.116.11/29
We can use 18.104.22.168/29 fine no issue on WAN2 however we have a requirement to use IP's in the 217.111 range issued on the same circuit but we cant seem to do this on the MX, on the ASA it appears to just route to the interface and works but I cant see a way to get this second range working on WAN2 on my MX, is it possible?
It looks like so far as its not part of the same subnet it wont allow routing to it.
Re: Use a range from an ISP on an MX WAN interface which isnt in the same subnet
Your carrier has the 22.214.171.124/29 subnet on the actual WAN link, but the 126.96.36.199/29 doesn’t actually exist on the link. As Philip said, you just need to create a NAT for these addresses on the MX and the carrier needs to route the 188.8.131.52/29 subnet to the IP address that is on the WAN port of the MX. The MX doesn’t do any checks around whether or not the public IP for a NAT can be reached, it just assumes it can be and just listens for the IP address.
If you want to use the public IP addresses on the LAN side of the MX you just create a 1:1 NAT for each of the six useable IP addresses, with the same public IP for Public IP and LAN IP. If you want to use private IPs on the LAN then just use the public IP for the Public IP, and the private IP for the LAN IP.