[SR-Users] blocking call in between two kamailio proxy

[Daniel Tryba]

On Tuesday 01 September 2015 08:58:30 Daniel-Constantin Mierla wrote:
> if($rd!=$fd) {
>     send_reply("403", "Call outside the domain");
>     exit;
> }

What is stopping from people from setting $fd to the desired domain? Isn't $ad 
a better var. for this since it isn't dependend on user supplied data (well it 
is but then authenication will fail). Otherwise $fd should be used for 
authentication challenge/response.