On 3/16/07, Jobson Andrade <jandrade(a)obelisknet.com.br> wrote: I though you just wanted to change the From header. The 'uac_replace_from()' just changes this header in the sip message. To make client authentification, you need to configure a failure route and use 'uac_auth()' in it. There is an example showing exactly what you are looking for at: http://www.voice-system.ro/docs/uac/ar01s06.html#ex_auth -- Regards, -vma .