I have made a SER(SIP express router) server. i have try it in local network and it work. the client can call each other. when i try the server use IP public. a have a problem. i try using 2 client.one client uses static ip and other client uses ip public. local client can call and comunicate with the public client. but when public client call local client, it doesn't work. there some error message "408 : request time out". for information local client was under a firewall. Can you tell me the couse of error? is this because of the firewall? or there some script or other setting that must be added to the server.? thanks for help, i wait the answer as soon as possible.