I have my astesisk box up and running now, and it is great.
I have several external voip phones but I am a paranoid guy, so I only allowing that particular IP in my firewall.
I have done all the other security tip, like fail2ban, alwaysauthreject=yes and so on.
But what I realy want is a way to allow that hardware to the asterisk. Is that possible? like a mac adress?
The reason is that the external klients have dynamic ip, so there is a lot of reporting ip back and forward.