The following instructions apply if you have a Linux platform and want libpcap to support the 'ACN' WAN/LAN router product from from SITA (http://www.sita.aero) This might also work on non-Linux Unix-compatible platforms, but that has not been tested. See also the libpcap INSTALL.txt file for further libpcap configuration options. These additions/extensions have been made to PCAP to allow it to capture packets from a SITA ACN device (and potentially others). To enable its support you need to ensure that the distribution has a correct configure.ac file; that can be created if neccessay by using the normal autoconf procedure of: aclocal autoconf autoheader automake Then run configure with the 'sita' option: ./configure --with-sita Applications built with libpcap configured in this way will only detect SITA ACN interfaces and will not capture from the native OS packet stream. The SITA extension provides a remote datascope operation for capturing both WAN and LAN protocols. It effectively splits the operation of PCAP into two halves. The top layer performs the majority of the work, but interfaces via a TCP session to remote agents that provide the lower layer functionality of actual sniffing and filtering. More detailed information regarding the functions and inter-device protocol and naming conventions are described in detail in 'pcap-sita.html'. pcap_findalldevs() reads the local system's /etc/hosts file looking for host names that match the format of IOP type devices. ie. aaa_I_x_y and then queries each associated IP address for a list of its WAN and LAN devices. The local system the aggregates the lists obtained from each IOP, sorts it, and provides it (to Wireshark et.al) as the list of monitorable interfaces. Once a valid interface has been selected, pcap_open() is called which opens a TCP session (to a well known port) on the target IOP and tells it to start monitoring. All captured packets are then forwarded across that TCP session back to the local 'top layer' for forwarding to the actual sniffing program (wireshark...) Note that the DLT_SITA link-layer type includes a proprietary header that is documented as part of the SITA dissector of Wireshark and is also described in 'pcap-sita.html' for posterity sake. That header provides: - Packet direction (in/out) (1 octet) - Link layer hardware signal status (1 octet) - Transmit/Receive error status (2 octets) - Encapsulated WAN protocol ID (1 octet)