Does the R3 accept a /31 mask in the static IP WAN settings?

[Iced Soul]

Hey, quick question before I sign up with a new ISP. They're giving me a dedicated fiber line with a static IP on a /31 (mask 255.255.255.254). Their ONT will be in bridge mode going straight into the R3, no PPPoE.

Does the R3 accept a /31 mask in the static IP WAN settings?

Thanks!

[Netduma Fraser]

You don't need the static IP in WAN Settings, you'll just receive the IP from the provider so it'll work just fine!

[Iced Soul]

On 9/16/2026 at 5:07 AM, Netduma Fraser said:

You don't need the static IP in WAN Settings, you'll just receive the IP from the provider so it'll work just fine!

Thanks! The thing is there's no DHCP on this one. It's a point to point handoff, so the ISP just gives me the IP, mask and gateway to type in manually, nothing hands out an address.

So what I really need to know is whether the static IP page on the R3 accepts 255.255.255.254 as the subnet mask. Some routers refuse anything smaller than a /30. 

[Krush]

Salut !

Juste pour mon information personnelle, quel FAI/Pays te propose cette configuration ?

[Iced Soul]

12 minutes ago, Krush said:

Salut !

Juste pour mon information personnelle, quel FAI/Pays te propose cette configuration ?

Salut!!

Brésil. Un opérateur régional du dans le nord-est. C'est leur offre pro / lien dédié : ONT en bridge, pas de PPPoE, IP publique fixe livrée sur un /31 en point à point. Ça change de la fibre grand public ici, qui est presque toujours en PPPoE avec du CGNAT.

[Krush]

Do they provide you with a router downstream of the ONT?

[Iced Soul]

4 minutes ago, Krush said:

Do they provide you with a router downstream of the ONT?

No, nothing after the ONT. It stays in bridge and that's it.

They did ask if I had a MikroTik, since that's what they normally install and configure on these links, but I told them I'll use my own router. So the R3 will be the only router on the line, which is why the static IP has to go on its WAN port.

[Krush]

Dans le principe c'est possible, mais pour tempérer... vous avez confirmation de Fraser  ! 😉