pcap-linktype(7) — Linux manual page

NAME | DESCRIPTION | SEE ALSO | COLOPHON

PCAP-LINKTYPE(7)     Miscellaneous Information Manual    PCAP-LINKTYPE(7)

NAME         top

       pcap-linktype - link-layer header types supported by libpcap

DESCRIPTION         top

       For a live capture or ``savefile'', libpcap supplies, as the
       return value of the pcap_datalink(3PCAP) routine, a value that
       indicates the type of link-layer header at the beginning of the
       packets it provides.  This is not necessarily the type of link-
       layer header that the packets being captured have on the network
       from which they're being captured; for example, packets from an
       IEEE 802.11 network might be provided by libpcap with Ethernet
       headers that the network adapter or the network adapter driver
       generates from the 802.11 headers.  The names for those values
       begin with DLT_, so they are sometimes called "DLT_ values".

       The pcap_datalink_val_to_name(3PCAP) and
       pcap_datalink_name_to_val(3PCAP) routines can be used to translate
       between DLT_ values and names.  Some capture devices support more
       than one link-layer header type.  The pcap_list_datalinks(3PCAP)
       routine can be used to retrieve the supported link-layer header
       types of a capture device and the pcap_set_datalink(3PCAP) routine
       can be used to change the link-layer header type of a capture
       device.

       The values stored in the link-layer header type field in the
       savefile header are, in most but not all cases, the same as the
       values returned by pcap_datalink().  The names for those values
       begin with LINKTYPE_.

       The link-layer header types supported by libpcap are described at
       https://www.tcpdump.org/linktypes.html .

SEE ALSO         top

       pcap(3PCAP)

COLOPHON         top

       This page is part of the libpcap (packet capture library) project.
       Information about the project can be found at 
       ⟨http://www.tcpdump.org/⟩.  If you have a bug report for this
       manual page, see ⟨http://www.tcpdump.org/#patches⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨https://github.com/the-tcpdump-group/libpcap.git⟩ on 2025-08-11.
       (At that time, the date of the most recent commit that was found
       in the repository was 2025-08-10.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there is
       a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

                              1 October 2024             PCAP-LINKTYPE(7)

Pages that refer to this page: pcap_datalink(3pcap)pcap_free_datalinks(3pcap)pcap_list_datalinks(3pcap)pcap_open_dead(3pcap)pcap_open_dead_with_tstamp_precision(3pcap)pcap-savefile(5)