System IP Address - Should I use RFC1918 VS unique facticious IP addresses

[jgardner150]

Quick question about the system IP address assigned to each vEdge router and vSmart controller in a deployment. I get that the main purpose is to act as a unique router ID, but I've noticed that their documentation is using ip addresses like 1.1.1.1 or 2.2.2.2 and some are RFC1918... Are the system IP addresses supposed to be rout-able outside of the SD-WAN environment?  My first thought is can I use these like a loop back interface for direct SSH access? If yes than I am thinking it would be best to stick to RFC1918 address space that is able to route on my internal network.

[Jayesh Singh · Accepted solution]

Hi,

The system IP address can be any IPv4 address except for 0.0.0.0/8, 127.0.0.0/8, and 224.0.0.0/4, and 240.0.0.0/4 and later.

As you got it right, system ip is for the interface named system that is placed in vpn0 and port type is loopback. So system ip has to be unique in vpn0, no other interface in vpn0 should have same ip.

For device management purposes, it is recommended as a best practice that you also configure the same system IP address on a loopback interface that is located in a service-side VPN that is an appropriate VPN for management purposes. You use a loopback interface because it is always reachable when the router is operational and when the overlay network is up. 

Hope this answers your query.

Thanks,

Jayesh

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