OK, now it's clear for me (that the browser will choose method). But now I should enable fallback method to my negotiate squid_kerb_auth, becaouse Skype and other stuff won't work with negotiate helper. Can I use squid_kerb_auth both in negotiate and in basic mode? If browser is ok (IE8, IE9, FF, Chrome) - negotiate will fork fine. Else - basic auth. auth_param negotiate program /usr/lib/squid3/squid_kerb_auth auth_param negotiate children 5 auth_param negotiate keep_alive on auth_param basic program /usr/lib/squid3/squid_kerb_auth auth_param basic children 5 auth_param basic keep_alive on Regards