When a SIP phone get the SIP Controller List successfully from the settings file, it should forget all previously learned values. It seems like some caching must be going on. If I set a group on my phone, for example, that causes the phone to register to my lab Session Managers, the SIP proxy list still contains the IPs for my production SMs. This causes unnecessary traffic to the production SMs and sometimes some registration issues. This also happens when a phone is taken home by the customer. They might set the correct group to get SBC addresses, but the phone still remembers and tries the internal SM addresses, which aren't reachable and causes sluggishness signing the phone in. The should use cached previous values when it's unable to reach the file server, or maybe when it's unable to login to the SM that are in the controller list (and thus should try a cached BSM IP).