Conntrack classifies a packet to a flow based on protocol no, srcip, destip, srcport, and destport.
A sample output is shown below,
[NEW] udp 17 30 src=192.168.2.100 dst=192.168.2.1 sport=57767 dport=53 [UNREPLIED] src=192.168.2.1 dst=192.168.2.100 sport=53 dport=57767
Here, what's the need of reply srcip, reply destip, reply srcport, reply destport? (Since we can imply these information from original srcp ip, original destip, original srcport, original destport) Is it just for avoiding for confusion, or anyother reasons behind this?