A method in a system for providing information about an association between an IP address of a UE and an ICCID of a SIM card used in the UE in a first security domain to an entity in a second security domain. The system comprises a MME, an HSS and a PDN-GW. The method comprises the MME retrieving at least the ICCID and optionally an IP address for the UE from the HSS, and sending the ICCID and optionally the IP address towards the PDN-GW. The method comprises the HSS receiving a request from the MME, and sending the ICCID and optionally the IP address to the MME. Still further, the method comprises the PDN-GW receiving the ICCID and optionally the IP address, if no IP address is received then the PDN-GW assigning an IP address, associating the IP address with the ICCID and informing the entity in the second security domain about the association between the IP address and ICCID in the first security domain.