Connect a FritzBox to an Asterisk server

Hi there,

could you please be so kind to give me an advice on whether the following idea makes sense and whether it can be set up using Asterisk?

The starting point is that standard analog telephones plugged into one of the recent FritzBoxes can be connected by the FritzOS firmware to SIP servers. My first question is: can this SIP server be an Asterisk server that is running on the same local network as the FritzBox?

If yes, would it be possible to forward the phone’s signal from this Asterisk server to another Asterisk server that is NOT on the local network (but somewhere else on the internet) in a ZRTP-encrypted way? (One possibility I could imagine is that both Asterisk servers are connected to some external SIP registry service that allows ZRTP. Is this a sensible idea?)

The full setup could be such that I would dial some specific number on my standard phone #1, upon which the signal gets sent through the FritzBox #1 to my local Asterisk server #1, from which it gets forwarded to the remote Asterisk server #2 with the help of external SIP registries, then from the remote Asterisk server #2 the call gets decrypted and routed unencryptedly on the remote network to a FritzBox #2 on that same remote network, thereby making a certain standard analog phone #2 plugged into that FritzBox #2 ring. If that phone #2 is being picked up, a call should be established that is encrypted for that part of the link which is between the two Asterisk servers. Do my mumblings make sense, and if so, would it be possible to set it all up using the Asterisk software?

Thanks so much, and kind regards!

There is no native ZRTP support in Asterisk.

Asterisk supports encrypted signaling and media with TLS and SRTP.

Thanks for your reply, johnkiniston.

Well if that is such, then let me rephrase my original posting with ZRTP replaced by SRTP and with the two Asterisk servers connecting directly to each other without external SIP servers involved.

Thanks and kind regards

Yes, You can trunk between two asterisk servers without any external resources. You just need one end to have a static IP address.

Thanks, johnkiniston. Are there any tutorials or documentation that you can think of that describe something of this sort that you could point me to in order to help me get started?

Kind regards