Chapter 4 FortiOS Carrier : GTP identity filtering : Other identity and location based information elements : Access Point Number (APN) : International Mobile Equipment Identity (IMEI)
  
International Mobile Equipment Identity (IMEI)
IMEI is a unique 15-digit number used to identify mobile devices on mobile networks. It is very much like the MAC address of a TCP/IP network card for a computer. It can be used to prevent network access by a stolen phone — the carrier knows the mobile phone’s IMEI, and when it is reported stolen that IMEI is blocked from accessing the carrier network no matter if it has the same SIM card as before or not. It is important to note that the IMEI stays with the mobile phone or device where the other information is either location based or stored on the removable SIM card.
IMEI type is part of advanced filtering configuration. See “Configuring advanced filtering in FortiOS Carrier”.