title: How a WireShark is Knowing saved Pcap files includes FCS or not?
body: <p>I am using a wireshark. I sniffed packets with FCS using wireshark and saved into pcap file in HardDisk. At the running time it can know FCS is included or not. But my doubt is, when I open a saved pcap file using wireshark how it is knowing whether the saved file is captured with FCS or not?
  How wireshark is differentiating files with FCS?
  Is there any variable in pcap file to know this?</p>