Hello.
I’m a bit confused about Proxy Arp. I have enabled a PPTP server and bound it to the default DHCP server, so that the connected user has direct access to my network.
Where do I enable Proxy-Arp, because I can see the option under all Interface ports and under Ethernet ports. I currently have it enabled under bridge1 (which includes Ethernet ports 1-10 and both WiFis).
What would happen if I enabled it everywhere, under all interfaces and ethernet ports itself?
You may have used the same IP pool for VPN clients, but they do not use DHCP for address allocation.
Proxy-arp should be enabled on the same local interface which has the IP address, so the parent bridge rather than the child ethernet and wireless interfaces. Enabling on an interface which has no IP address should do nothing, but there could possibly be unexpected side-effects.
Also stop using PPTP, it has well know vulnerabilities dating back at least 8 years.
Sadly there isn’t really a PPTP alternative, unless you count EoIP, but then all of my friends should own a Mikrotik router.
There are plenty of other VPNs available - plain IPsec, L2TP/IPsec, Open VPN, SSTP
Is it possible to configure any of them to use a Mikrotik as host, like PPTP can? Open VPN needs a dedicated server right?
All of those I mentioned have both client and server support:
https://wiki.mikrotik.com/wiki/Manual:IP/IPsec - there are some examples in section 17
https://wiki.mikrotik.com/wiki/Manual:Interface/OVPN - there are some limitations (no UDP mode or LZO compression)
https://wiki.mikrotik.com/wiki/Manual:Interface/SSTP