Dear Sirs/ Ma'ams, I am an undergraduate student following the B Eng (Hons) Software Engineering degree program at University of Westminster, UK. As for my final year research project I am implementing a packet security enhancement module. The concept includes capturing of packets via the use of libnetfilter and apply necessary security implementations. I was able to successfully capture packets and extract it relevant data where I store the IP address as unsigned int. However, I have the requirement of identifying the packets destination IP's address family. I tried many ways, which only lead me to user space implementations, not C linux kernel module programming. During my research I just came across %pI4 and %pI6 which formats and displays the Ip address, not give out its address family, i. e. IPv6 or IPv4. I would be really grateful if you experts would help me get through this obstacle. any references or examples to identify the IP address family (IPv4/ IPv6) of the IP (which is store in unsigned int variables) will be highly appreciated. Thank you, Best Regards, H. Hasitha Shan P.S. I apologize in advance if this question has an obvious answer, but as I am a novice in this area, my research lead me to dead ends for weeks and your help will be very much appreciated.