SIP ALG should be disable into the router. I have manage to run following command to disable SIP ALG, no ip nat service sip udp port 5060. I cannot find any other command to disable SIP ALG. IP Phone provider said SIP ALG should be disable router wide and not just specific to one port. have manage to run following command to disable SIP ALG, no ip nat service sip udp port 5060. I cannot find any other command to disable SIP ALG. IP Phone provider said SIP ALG should be disable router wide and not just specific to one port.