RouterOS subnet zero

RouterOS General
1

Hi,

does RouterOS support subnet-zero? I have no problem with Cisco, but now I need to set it up with Mikrotik and no luck.

Subnet zero means using network address as interface address:

add address=1.2.3.122/30 interface=ether7-uplink network=1.2.3.120
add address=1.2.3.120/32 interface=ether7-uplink network=1.2.3.120

The second IP address is subnet-zero and is unreachable. I’ve tried /30 mask for the second address too, and still no luck.

Do I do anything wrong or is subnet-zero feature unsupported?

Thank you.

2

Using a /32 subnet mask is possible and works properly. I’ve had a couple of RB’s with loopback interfaces addressed that way in my network.
Is the ether7-uplink interface up? If it’s not up, the routing table will show the connected subnet as unreachable.

Post the output of these commands, maybe we’ll find out what’s wrong.
/ip route exp com
/ip route print
/ip address exp com

3

I know that /32 netmasks work properly, in use it frequently, mostly with OSPF.

But I would like to use IP address with all-zeros in host portion of IP address (address of network). My ISP gave me /30 subnet of public addresses for my router (.121/30 is my gateway - his router, .122/30 is my router’s external interface, .123/30 is broadcast, .120/30 is network address). I would like to use .120/30 (or .120/32) as second public IP of my router.

Is it possible?

After some googling I have found that this is not subnet-zero, so sorry for misunderstanding. So maybe this intentionally doesn’t work.

4

Nope, sorry, it won’t work the way you described it.