Also, ensure that your version of Net::Pcap and the libpcap it is using are current enough to support wireless capture. The MAC frame for wireless (which is CSMA/CA) is not the same as that for Ethernet (which is CSMA/CD). Older versions of libpcap do not support wireless frames. I do not know whether or not any versions of Net::Pcap support capturing wireless frames, or whether they only support accessing the pseudo-Ethernet version.