Why aren't you developing a VoIP anti blocage solution ?
Yes VoIP blocage is something that should not exist, that's not real internet.
Technically, an anti-blocage solution requires a server infrastructure that
linphone.org cannot afford, and we don't want to fight against anybody.
Also, there are operators that don't block VoIP in many countries.
This is not really relevant to this question. I am not asking about the blocking of VoIP by mobile operators, or how to unblock them. I am asking about blocking unwanted calls originating from untrusted sources.
See introductory tutorial at
<http://www.howtogeek.COM/177621/the-beginners-guide-to-iptables-the-linux-firewall/>
Firewall is one to to deal with this, however a more affective way is to configure the client to block unwanted calls from unwanted sources.
You may find this article of interest.
<http://blog.sipvicious.ORG/2012/12/if-sipvicious-gives-you-ring.html>
Thanks, but this only provides suggestions without explaining how to implement them. In fact, it suggests precisely what I'm asking, to configure the client to "only allow it to be contacted by the provider".
Linphone is of-course the client here, hence my question on this list is to find out how to implement that solution.
Nabeel