Hi

I work at an ISP and recently we installed a Mikrotik router to act as a second NAS at our network (the first one is Cisco). Clients are using PPPoE and are offered dynamic public IP from the pool allocated at the Mikrotik router. The problem that we have is that the client gets the same IP after disconnect/connect. This does not happen with the Cisco router. We are using RadiusManager for authentication. What can we do to make the client get a different IP after disconnect/connect ???

When a user disconnect and connect again in short time this is something that looks normal because of arp table age!

When a user disconnect and connect again in short time this is something that looks normal because of arp table age!

This happens even if the user is reconnected after 5min.


Also since there is no entry at the IP/Arp table what can we do to force the client get another IP

Mikrotik as far as I remember, allocates IPs out of the pools on a first-come, first-served basis. Which ever first IP is available in the pool, will be allocated.

If user A disconnects, no one else connects, and user A reconnects an hour later, they will get the same IP.
If user A disconnects, user B connects, use B will get user's A IP address. User A will in this case get a different IP if they reconnect whilst user B is still connected.

This is unfortunately just how Mikrotik's IP Pools and IP assignments work. There isn't anything that can be done about it. You can't force a different IP to a user on a reconnect.

If you want (and insist on) completely random IP addresses, assign the addresses randomly using Radius and the Framed-IP-Address attribute. You'll have to keep track of which IPs are / are not, in use however.

hello, did you solve the problem?