Connecting two Mikrotik routers over /31 subnet

RouterOS General
1

Hi all,

I’ve been playing around with /31 subnetting and we have a new customer site where we’d like to adopt RFC3021 Point-to-Point subnetting to conserve our IPv4 resources as they become increasingly more difficult to obtain.

I haven’t encountered an issue like this before, and although I’m relatively a beginner with networking, I cannot see any obvious issues. I’m primarily from a carrier ethernet background. Whilst our network engineer is away on holidays, I wanted to try working through this one on my own, and I’ve got to the point where I need a fresh pair of eyes to have a look over everything to help figure this one out, and ultimately for me to further develop my skillset.

In addition to the below, I have put together a diagram to visually aid → https://pasteboard.co/JVPukh9FQts4.png

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We have two sites

  • Data Center (site A)
  • Customer (site B)

Things to note

  • The sites are connected using an MPLS circuit from a carrier, and this works completely fine. There are no issues with the MPLS circuit.
  • One of our /24 subnets is advertised over eBGP at the data center.
  • The actual IPs we are using differ from those listed within this topic, but still show the same concept.

How it’s configured
##Data Center (site A)

  • The associated interface is tagged with VLAN 300, and the interface IP is 144.144.144.0/31.
  • The route has a code: [DAC], dst. address of 144.144.144.0/31, gateway is the VLAN_300 sitting on the interface, the pref. src is 144.144.144.0 (auto-set, cannot change).
  • Address list has the VLAN_300 interface listed with an address of 144.144.144.0/31, network address of 144.144.144.0.
  • Note, the gateway indicates its reachable in the route list.
  • Cannot ping the customer router (144.144.144.1) from the terminal.

##Customer (site B)

  • The associated interface is tagged with VLAN 300, and the interface IP is 144.144.144.1/31.
  • The route has a code: [DAC], dst. address of 144.144.144.0/31, gateway is the VLAN_300 sitting on the interface, pref src is blank.
  • There is a second route with code [AS], dst. address of 0.0.0.0/0, gateway is 144.144.144.0, pref src is blank.

What I’ve tried

  • MAC Ping between site A and site B routers = SUCCESS
  • ICMP Ping between site A and site B routers = FAILED
  • Neighbor identification w/ correct information = SUCCESS
  • Check over address and route lists = CHECKED, NO ISSUES
  • Ensure no firewall or NAT rules exist = CHECKED, NONE