Do boost ASIO sockets automatically use multiple network interfaces? Efficiently? If not, how?

Question

I'm trying to determine if boost client & server endpoints will automatically use all available network interfaces.

I've read the two links that I've found on the subject, and it seems that it's possible, but which interface is chosen, if so?

Can a server endpoint accept connections on all interfaces? Will a client endpoint automatically seek the best connection, for example, where one internet connection connects to a local region with better connectivity to geographically nearer nodes available through one device yet to the internet at large with better connectivity to the rest of the world through another device?

If they do not automatically use all available interfaces, how can they be made to do so?

Answer 1

Can a server endpoint accept connections on all interfaces?

Yes.

Will a client endpoint automatically seek the best connection, for example, where one internet connection connects to a local region with better connectivity to geographically nearer nodes available through one device yet to the internet at large with better connectivity to the rest of the world through another device?

The client will choose the route that has the lowest cost as determined by its IP routing tables. Each intermediate router will do the same.