PPP users not able to ping Radius Server on same subnet

In a server with IP address 103.43.xx.x , I am assigning Public IPs to customers and also giving out Public dynamic IPs defined in IP pool all are in the subnet of 103.43.xx.0/24
The curious case is that the customers who are assigned IPs in RM-ACP are able to ping RM-server but all other customers that are getting IPs from Mikrotik-pool are not able to ping to RM-server
Can anyone suggest why is this happening ?

I don’t know what “RM-Server” is, but if your “RM-Server” has an IP in the same range 103.43.x.0/24 that you are assigning to PPP users, then your RM-Server is trying to ARP for those IPs in order to send a response back to the PPP users, and it never gets a response back because PPP isn’t Ethernet, is point-to-point (/32), and doesn’t use ARP.

You have 2 options:

  1. Have your “RM-Server” also connect to your RouterOS router with PPP.
  2. Set up an ARP proxy between your Ethernet network and your PPP users.

If your RouterOS router doing the PPP termination is on the same Ethernet L2 with your RM-Server and also has a 103.43.x.0/24 IP address, you can set “arp=proxy-arp” on the ethernet interface that has the 103.43.x.x IP address.

– Nathan