Why so many VPN connections?

Question

VPN

There is a pptp server on Mikrotik, 20 clients connect to it using the same login / password. But when I look at the list of clients on the server, I have a lot more of them. At the same time, some have the designation D (dinamic), and some DR (dinamic, running). There are currently 19 DRs connected, and 34 Ds. What is this D? where do they come from? It wasn't there before.

Answer 1

Most likely brut or DDOS. Create many open authorization sessions. So you can put the VPN to work and if you have branches with 1Skay on it, then it will result in loss of customers and losses.
I would recommend ordering a VLAN from the provider and starting a VPN on top of it if you need encryption. At worst, configure the firewall so that it beats off the left ones earlier.

Answer 2

There is a pptp server on Mikrotik

I recommend switching to l2tp, since pptp has holes, which we generally see. You ddos-yat.
The second point is setting up a rule that will reject such connections.
To you on the example of rdp
https://spw.ru/forum/threads/perebor-portov.548/
Protection from scanning
https://wiki.mikrotik.com/wiki/Drop_port_scanners
This means that there is an attempt to connect. This rule is created dynamically, not by hand.
Since there you can create by hand.