Method and apparatus for anonymous network access in the absence of a mobile subscriber identity module

A method and apparatus enabling a mobile user device (102) to anonymously access a network (108, 114) in the absence of a subscriber identity module (SIM) card (142) that includes an interim identity generator (138), positioned in the mobile user device, generating an interim international mobile subscriber identity (IMSI) in response to the SIM card not being positioned within the mobile user device. The interim IMSI is utilized for signaling exchanges requiring information corresponding to the SIM card when the SIM card is not inserted within the mobile user device. A user identity module (152, 154) detects the presence of the interim IMSI in a signaling message, and routes the signaling message to a first home location register (156), in response to the signaling message including the interim IMSI, which then computes and transmits an authentication triplet to the mobile user device. The user identity module routes the signaling message to a second home location register (150) in response to the signaling message not including the interim IMSI.