Hello ... What you are trying todo ... Could only be done un two ways... Way one : the easier and better... Lets kamailio do their work ... And put it un front of the asterisk servers Way two: the hardest one Correctly setup your DNS server. The setup you need for sending out different answers depending con the orig ip its calles 'split hirizont'. Also you will need a good dns-srv Support on your IP phones ... And Support for failback setup ... Not all models Support that ... I know snom terminals Support that. Forget about h323 ... Its a dead cat Best regards -- Raúl Alexis Betancor Santana Dimensión Virtual S.L. Rafael Carvallo <shaoranrch(a)gmail.com> wrote: