Hello, Thank you for your help but I don't understand how you can make it. Here my configuration that I try: #Replae The Nas-Ip6address by Proxy-IP attr_rewrite overwrite_nasip { attribute = "NAS-IP-Address" searchfor = ".*" packet = packet replacewith = "10.28.65.130" max_matches = 1 } # Dev Eqpt : 192.168.48.0/24 attr_rewrite dev_equipment { attribute = "Calling-Station-Id" searchfor = ".*" packet = packet replacewith = "Dev" --> Replace String Dev for all Eqpts but not for 192.168.48.0/24!! max_matches = 1 } preproxy { files overwrite_nasip dev_equipment } Here what I want : 1. If [ NAS-IP-Address =~ 192.168.48.* ] Calling-Station-Id = Dev else if [ NAS-IP-Address =~ 192.168.49.* ] Calling-station-id = Prod else Calling-station-id = Any fi fi 2. the proxy forwards the access-request to the radius server 3. The radius server receives the acces-request If [ Nas-IP-Address == Proxy-IP and Calling-Station-Id == Dev ] instance_openldap-Ldap-Group == CiscoDev else If [ Nas-IP-Address == Proxy-IP and Calling-Station-Id = Prod ] instance_openldap-Ldap-Group == CiscoProd else instance_openldap-Ldap-Group == CiscoOthers fi fi Thank you for your assistance Nicolas.