recently my VOIP provider blocked access to his SIP servers for IP adresses outside my country. While I do travel a lot, access from foreign countries is a must for me. And I do have a Mikrotik router with static inetrnet IP address in my country, with private network behind it.
The idea is, could I somehow configure my router to be a “middleman” between my SIP client outside (either W7 or iphone), and VOIP provider’s SIP server, so that it would allow VOIP calls? I can always reconfigure the router for new foreign IP adress. I tried several firewall rules on the router myself, but the best I could get was that VOIP client did not immediately refuse the connection, but ended in waiting loop for registering to SIP server.
Thanks for ideas.
so far I’ve failed, neither W7 or iphone can connect, connection timeouts with no answer. But maybe it is something wrong with the line I am on now.
Also, as I am no familiar with VPN what is unclear to me, how VOIP client would know that it shall use VPN connection instead of direct one for reaching the public IP of SIP server? I suppose that when VPN is connected, then the direct connection to internet is still available. But this is my general question to VPN.
If you are trying to do this from a mobile network, I have encountered network operators that block certain types of traffic, including VPN traffic. So it is entirely possible.
Because you would tick the option on the phone that says to “send all traffic” over the VPN while the VPN is connected.
Another option would be to configure a SIP-based back-to-back-user-agent (B2BUA) PBX (like Asterisk) that sits on your home network and that connects to your VoIP provider, and which also allows your phone to connect to it. Not technically a “proxy” the way that the term is used specifically in the context of SIP, but probably more along the lines of what you were originally asking/thinking of. This would not be a RouterOS solution, though…it’s too specific of an application for a router operating system to list as a feature.