HA with port forwarding question. IP Alias?

[loganx1121]

So I'm kind of wondering what the IP Alias virtual IP is actually used for in a real world scenario and I'm wondering if it's for what I'm trying to do.

I have a Public IP space from my ISP, let's call it 192.168.1.1/27 for the sake of argument. Within that space, I have port forwarding setup and I've made firewall alias's to assign servers to Public IP's within that space. My connection with the ISP is a direct connection, meaning I'm not routing over some interim network to get to them, I just point at the gateway they gave me.

So if my primary firewall goes down, or I fail it over manually, will those port forwards still "just work", or is this where I would define the public IP of these servers as an "IP Alias" in the virtual IP's?

[Greelan]

IP Aliases are to assign additional IPs to interfaces on OPNsense. For example I use them to configure IPv6 ULAs

[FraLem]

Quite useful as well for 1:1 NAT
Rgds

[loganx1121]

Quite useful as well for 1:1 NAT
Rgds

I guess I'm not understanding.  Why would this be useful for 1:1 NAT?  Wouldn't the NAT by itself function?

[FraLem]

Should you require to full expose some of your equipment on your LAN network (lest say X.X.X.10..20) fully to your WAN network, (Y.Y.Y.210-220), then you would assign these IP Alias to your WAN interface and add a 1:1 NAT rule Y.Y.Y.210 -->X.X.X.10 and so forth.
The above mentioned LAN devices would be fully reachable from your WAN Network.

Hope it helps to clarify the application.

Regards