A method for configuration and performing of a liveness check using Internet key exchange messages, the method being performed by a user equipment , the method comprising: transmitting (S102), from the user equipment over an air interface to a core network node , a first Internet key exchange message comprising a configuration attribute indicating support of receiving a timeout period for liveness check, wherein the configuration attribute indicating support of receiving a timeout period for liveness check is a timeout period for liveness check attribute with length field set to zero, receiving (S104), at the user equipment over the air interface from the core network node, a second Internet key exchange message comprising a configuration attribute indicating a timeout period for said liveness check, performing (S106) said liveness check according to the configuration attribute indicating a timeout period for said liveness check, comprising: transmitting (S108) an informational request with no payload if a timeout period for liveness check attribute is included in the received configuration attribute indicating a timeout period for said liveness check, and in absence of receiving a cryptographically protected Internet protocol security, IPSec, packet or a cryptographically Internet key exchange packet during the timeout period for said liveness check, and wherein in absence of receiving an informational response in response to the transmitted informational request with no payload, performing one or more of: determining (S110) failure of the Internet key exchange security association; discarding (S112) any state information associated with the Internet key exchange security association; and/or discarding (S114) any Internet protocol security, IPSec, security associations negotiated using the Internet key exchange security association transmitting (S102), from the user equipment over an air interface to a core network node , a first Internet key exchange message comprising a configuration attribute indicating support of receiving a timeout period for liveness check, wherein the configuration attribute indicating support of receiving a timeout period for liveness check is a timeout period for liveness check attribute with length field set to zero, receiving (S104), at the user equipment over the air interface from the core network node, a second Internet key exchange message comprising a configuration attribute indicating a timeout period for said liveness check, performing (S106) said liveness check according to the configuration attribute indicating a timeout period for said liveness check, comprising: transmitting (S108) an informational request with no payload if a timeout period for liveness check attribute is included in the received configuration attribute indicating a timeout period for said liveness check, and in absence of receiving a cryptographically protected Internet protocol security, IPSec, packet or a cryptographically Internet key exchange packet during the timeout period for said liveness check, and wherein in absence of receiving an informational response in response to the transmitted informational request with no payload, performing one or more of: determining (S110) failure of the Internet key exchange security association; discarding (S112) any state information associated with the Internet key exchange security association; and/or discarding (S114) any Internet protocol security, IPSec, security associations negotiated using the Internet key exchange security association determining (S110) failure of the Internet key exchange security association; discarding (S112) any state information associated with the Internet key exchange security association; and/or discarding (S114) any Internet protocol security, IPSec, security associations negotiated using the Internet key exchange security association <EOS>