is the industry-standard tool for link-layer network access
in Windows environments: it allows applications to capture
and transmit network packets bypassing the protocol stack,
and has additional useful features, including kernel-level
packet filtering, a network statistics engine and support
for remote packet capture.
More details: www.winpcap.org
Sniffer of HiDownload Platinum use winpcap's
API to watch network traffic and identifying potential urls.