Limitations

Filtering

While WinPcap-NT allow you to run WinPcap applications with Napatech SmartNICs, you should be aware of a few limitations to fully take advantage of Napatech SmartNICs:

• Filtering in WinPcap (using pcap_setfilter()) is SW-based and does not utilize the filtering capabilities of Napatech SmartNICs. Filtering configured using ntpcap.ini is HW-based. You can also configure HW-based filtering using the ntpl tool.
• Napatech SmartNIC drivers do not provide file descriptors. Therefore it is not possible to get a valid OS file descriptor through pcap_fileno(), which returns -1. pcap_get_selectable_fd() also returns -1.
• pcap_set_promisc() has no effect on a Napatech WinPcap device, since this is always in promiscuous mode.

Unsupported functions

• Napatech SmartNIC drivers do not provide file descriptors. Therefore it is not possible to get a valid OS file descriptor through pcap_fileno(), which returns -1. pcap_get_selectable_fd() also returns -1.
• pcap_set_promisc() has no effect on a Napatech WinPcap device, since this is always in promiscuous mode.

Only one version of WinPcap

• Multiple versions of WinPcap cannot be installed on a Windows system. Before installation of WinPcap-NT, any existing WinPcap installation must be uninstalled. This can be done automatically by the WinPcap-NT Installer, or by using the uninstaller provided by the existing WinPcap installation.