[boost] Udp Socket

Asalam-o-Aliakum and Hi all, I am having a problem with boost udp socket. My program terminates after throwing exception "host unreachable". My questions: 1). why udp socket cares for host it should just send data out of its own port and its job is done? 2). And how it knows that host is not available if udp is connection less protocol? 3). And another simple question how to avoid program termination on this exception? Best Regards; Sami Ul Haq