RouterOS supports Point-to-Point Tunneling Protocol (PPTP) which is one of the obsolete methods for implementing a VPN.
PPTP has many known security issues and we are not recommending to use it. However, this protocol is integrated into common operating systems and it is easy to set it up. PPTP can be useful in networks where security concerns are not considered.
PPTP traffic uses TCP port 1723 and IP protocol GRE (Generic Routing Encapsulation, IP protocol ID 47), as assigned by the Internet Assigned Numbers Authority (IANA). PPTP can be used with most firewalls and routers by enabling traffic destined for TCP port 1723 and protocol 47 traffic to be routed through the firewall or router. PPTP includes PPP authentication and accounting for each PPTP connection. Full authentication and accounting of each connection may be done through a RADIUS client or locally.
An interface is created for each tunnel established to the given server. There are two types of interfaces in the L2TP server's configuration:
- Static interfaces are added administratively if there is a need to reference the particular interface name (in firewall rules or elsewhere) created for the particular user;
- Dynamic interfaces are added to this list automatically whenever a user is connected and its username does not match any existing static entry (or in case the entry is active already, as there can not be two separate tunnel interfaces referenced by the same name);
Dynamic interfaces appear when a user connects and disappear once the user disconnects, so it is impossible to reference the tunnel created for that use in router configuration (for example, in firewall), so if you need persistent rules for that user, create a static entry for him/her. Otherwise, it is safe to use a dynamic configuration.
The PPTP server (access concentrator) supports multiple servers for each interface - with differing service names. The access concentrator name and PPTP service name are used by clients to identify the access concentrator to register with. The access concentrator name is the same as the identity of the router displayed before the command prompt. The identity may be set within the /system identity submenu.
To enable the PPTP server:
The following example demonstrates how to set up a PPTP client with username "MT-User", password "StrongPass" and server 192.168.62.2:
On the other side we simply enable the PPTP server and create a PPP secret for a particular user: