I have a network comprised of 3 sites... each site has a Mikrotik and they are L2TP VPN's between the three. LAN-wise we have the networks 10.0.0.0/22, 10.0.4.0/22 and 10.0.8.0/22 with routing set up so that everything can connect to everything else.

Needed to have external access to the network so last night I tried to set up a PPTP VPN server on each of the routers. That part went well, get connected and can ping the router but not access anything else on the LAN. After some reading I tried to turn on proxy-arp on the bridges on each of the routers which seemed to resolve the issue, pinged to my hearts content and everything seemed fine.

Came in to the office this morning and that's where things had gone downhill. The sip phones at the two remote sites were not connecting to the server in the main office and when I was trying to troubleshoot, accessing the web interface of the phones and of the phone server (among some other things) seemed really sluggish. I was able to ping the phone server from the remote sites and was able to ping the phones from the main office but SIP would simply throw an error and was seeing nothing in terms of registrations at the server side... that made things even more confusing. Just to be on the safe side I did reboots of all 3 routers but no change. At that point I started to roll back what I'd done the night before, the first of which I switched the bridge interfaces back from "proxy-arp" back to simply "arp-enabled" as they were previously. Bingo, phones are back online and otherwise everything's running normally.

Soooooo... suggestions on how I can configure this to have the best of both worlds... ie. my LAN working fine, and the PPTP VPN able to access the resources on the LAN also?

Thanks for any input!
Mike

Did you create the nat rules for vpn and routes for these address?