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libpcap installation notes

Libpcap can be built either with the configure script and make, or with CMake and any build system supported by CMake.

To build libpcap with the configure script and make:

  • If you build from a git clone rather than from a release archive, run ./ (a shell script). The script will build the configure and files.

On some system, you may need to set the AUTORECONF variable, like: AUTORECONF=autoreconf-2.69 ./ to select the autoreconf version you want to use.

  • Run ./configure (a shell script). The configure script will determine your system attributes and generate an appropriate Makefile from The configure script has a number of options to control the configuration of libpcap; ./configure --help will show them.

  • Next, run make. If everything goes well, you can su to root and run make install. However, you need not install libpcap if you just want to build tcpdump; just make sure the tcpdump and libpcap directory trees have the same parent directory.

On OpenBSD, you may need to set, before the make, the AUTOCONF_VERSION variable like: AUTOCONF_VERSION=2.69 make

To build libpcap with CMake and the build system of your choice, from the command line:

  • Create a build directory into which CMake will put the build files it generates; CMake does not work as well with builds done in the source code directory as does the configure script. The build directory may be created as a subdirectory of the source directory or as a directory outside the source directory.

  • Change to the build directory and run CMake with the path from the build directory to the source directory as an argument. The -G flag can be used to select the CMake "generator" appropriate for the build system you're using; various -D flags can be used to control the configuration of libpcap.

  • Run the build tool. If everything goes well, you can su to root and run the build tool with the install target. Building tcpdump from a libpcap in a build directory is not supported.

An uninstall target is supported with both ./configure and CMake.

DO NOT run the build as root; there is no need to do so, running anything as root that doesn't need to be run as root increases the risk of damaging your system, and running the build as root will put files in the build directory that are owned by root and that probably cannot be overwritten, removed, or replaced except by root, which could cause permission errors in subsequent builds.

If configure says:

configure: warning: cannot determine packet capture interface
configure: warning: (see file for more info)

or CMake says:

cannot determine packet capture interface

(see the file for more info)

then your system either does not support packet capture or your system does support packet capture but libpcap does not support that particular type. (If you have HP-UX, see below.) If your system uses a packet capture not supported by libpcap, please send us patches; don't forget to include an autoconf fragment suitable for use in

It is possible to override the default packet capture type with the --with-pcap option to ./configure or the -DPCAP_TYPE option to CMake, although the circumstances where this works are limited. One possible reason to do that would be to force a supported packet capture type in the case where the configure or CMake scripts fails to detect it.

You will need a C99 compiler to build libpcap. The configure script will abort if your compiler is not C99 compliant. If this happens, use the generally available GNU C compiler (GCC) or Clang.

You will need either Flex 2.5.31 or later, or a version of Lex compatible with it (if any exist), to build libpcap. The configure script will abort if there isn't any such program; CMake fails if Flex or Lex cannot be found, but doesn't ensure that it's compatible with Flex 2.5.31 or later. If you have an older version of Flex, or don't have a compatible version of Lex, the current version of Flex is available here.

You will need either Bison, Berkeley YACC, or a version of YACC compatible with them (if any exist), to build libpcap. The configure script will abort if there isn't any such program; CMake fails if Bison or some form of YACC cannot be found, but doesn't ensure that it's compatible with Bison or Berkeley YACC. If you don't have any such program, the current version of Bison can be found here and the current version of Berkeley YACC can be found here.

Sometimes the stock C compiler does not interact well with Flex and Bison. The list of problems includes undefined references for alloca(3). You can get around this by installing GCC.

Linux specifics

On Linux, libpcap will not work if the kernel does not have the packet socket option enabled; see this file for more information.

Solaris specifics

If you use the SPARCompiler, you must be careful to not use the /usr/ucb/cc interface. If you do, you will get bogus warnings and perhaps errors. Either make sure your path has /opt/SUNWspro/bin before /usr/ucb or else:

setenv CC /opt/SUNWspro/bin/cc

before running configure. (You might have to do a make distclean if you already ran configure once).

See this file for more up to date Solaris-related information.

HP-UX specifics

If you use HP-UX, you must have at least version 9 and either the version of cc that supports C99 (cc -AC99) or else use the GNU C compiler. You must also buy the optional streams package. If you don't have:


then you don't have the streams package. In addition, we believe you need to install the "9.X LAN and DLPI drivers cumulative" patch (PHNE_6855) to make the version 9 DLPI work with libpcap.

The DLPI streams package is standard starting with HP-UX 10.

The HP implementation of DLPI is a little bit eccentric. Unlike Solaris, you must attach /dev/dlpi instead of the specific /dev/* network pseudo device entry in order to capture packets. The PPA is based on the ifnet "index" number. Under HP-UX 9, it is necessary to read /dev/kmem and the kernel symbol file (/hp-ux). Under HP-UX 10, DLPI can provide information for determining the PPA. It does not seem to be possible to trace the loopback interface. Unlike other DLPI implementations, PHYS implies MULTI and SAP and you get an error if you try to enable more than one promiscuous mode at a time.

It is impossible to capture outbound packets on HP-UX 9. To do so on HP-UX 10, you will, apparently, need a late "LAN products cumulative patch" (at one point, it was claimed that this would be PHNE_18173 for s700/10.20; at another point, it was claimed that the required patches were PHNE_20892, PHNE_20725 and PHCO_10947, or newer patches), and to do so on HP-UX 11 you will, apparently, need the latest lancommon/DLPI patches and the latest driver patch for the interface(s) in use on HP-UX 11 (at one point, it was claimed that patches PHNE_19766, PHNE_19826, PHNE_20008, and PHNE_20735 did the trick).

Furthermore, on HP-UX 10, you will need to turn on a kernel switch by doing

echo 'lanc_outbound_promisc_flag/W 1' | adb -w /stand/vmunix /dev/mem

You would have to arrange that this happens on reboots; the right way to do that would probably be to put it into an executable script file /sbin/init.d/outbound_promisc and making /sbin/rc2.d/S350outbound_promisc a symbolic link to that script.

Finally, testing shows that there can't be more than one simultaneous DLPI user per network interface.

See this file for more information specific to HP-UX.

AIX specifics

See this file for information on installing libpcap and configuring your system to be able to support libpcap.

other specifics

If you are trying to do packet capture with a FORE ATM card, you may or may not be able to. They usually only release their driver in object code so unless their driver supports packet capture, there's not much libpcap can do.

If you get an error like:

tcpdump: recv_ack: bind error 0x???

when using DLPI, look for the DL_ERROR_ACK error return values, usually in /usr/include/sys/dlpi.h, and find the corresponding value.

Description of files

CHANGES		    - description of differences between releases
ChmodBPF/*	    - macOS startup item to set ownership and permissions on /dev/bpf*
CMakeLists.txt	    - CMake file	    - guidelines for contributing
CREDITS		    - people that have helped libpcap along	    - this file
LICENSE		    - the license under which tcpdump is distributed	    - compilation rules (input to the configure script)	    - description of distribution
doc/README.aix	    - notes on using libpcap on AIX
doc/README.dag	    - notes on using libpcap to capture on Endace DAG devices
doc/README.hpux	    - notes on using libpcap on HP-UX
doc/README.linux    - notes on using libpcap on Linux
doc/README.macos    - notes on using libpcap on macOS
doc/README.septel   - notes on using libpcap to capture on Intel/Septel devices
doc/README.sita	    - notes on using libpcap to capture on SITA devices
doc/ - notes on using libpcap on Solaris
doc/ - notes on using libpcap on Win32 systems (with Npcap)
VERSION		    - version of this release
aclocal.m4	    - autoconf macros
arcnet.h	    - ARCNET definitions
atmuni31.h	    - ATM Q.2931 definitions	    - build configure and (run this first)
bpf_dump.c	    - BPF program printing routines
bpf_filter.c	    - BPF filtering routines
bpf_image.c	    - BPF disassembly routine
charconv.c	    - Windows Unicode routines
charconv.h	    - Windows Unicode prototypes
config.guess	    - autoconf support
config.sub	    - autoconf support	    - configure script source
diag-control.h	    - compiler diagnostics control macros
dlpisubs.c	    - DLPI-related functions for pcap-dlpi.c and pcap-libdlpi.c
dlpisubs.h	    - DLPI-related function declarations
etherent.c	    - /etc/ethers support routines
ethertype.h	    - Ethernet protocol types and names definitions
fad-getad.c	    - pcap_findalldevs() for systems with getifaddrs()
fad-gifc.c	    - pcap_findalldevs() for systems with only SIOCGIFLIST
fad-glifc.c	    - pcap_findalldevs() for systems with SIOCGLIFCONF
fmtutils.c	    - error message formatting routines
fmtutils.h	    - error message formatting prototypes
ftmacros.h	    - feature test macros
testprogs/filtertest.c      - test program for BPF compiler
testprogs/findalldevstest.c - test program for pcap_findalldevs()
gencode.c	    - BPF code generation routines
gencode.h	    - BPF code generation definitions
grammar.y	    - filter string grammar
ieee80211.h	    - 802.11 definitions
install-sh	    - BSD style install script
lbl/os-*.h	    - OS-dependent defines and prototypes (if any)
llc.h		    - 802.2 LLC SAP definitions
missing/*	    - replacements for missing library functions
mkdep		    - construct Makefile dependency list
msdos/*		    - drivers for MS-DOS capture support
nametoaddr.c	    - hostname to address routines
nametoaddr.h	    - hostname to address prototypes
nlpid.h		    - OSI network layer protocol identifier definitions
optimize.c	    - BPF optimization routines
optimize.h	    - BPF optimization prototypes
pcap/bluetooth.h    - public definition of DLT_BLUETOOTH_HCI_H4_WITH_PHDR header
pcap/bpf.h	    - BPF definitions
pcap/can_socketcan.h - SocketCAN header
pcap/compiler-tests.h - compiler version comparison and other macros
pcap/dlt.h	    - Link-layer header type codes.
pcap/funcattrs.h    - function attribute macros
pcap/ipnet.h	    - Solaris IPnet definitions
pcap/namedb.h	    - public libpcap name database definitions
pcap/nflog.h	    - NFLOG-related definitions
pcap/pcap.h	    - public libpcap definitions
pcap/pcap-inttypes.h - header for OS-specific integer type includes
pcap/sll.h	    - public definitions of DLT_LINUX_SLL and DLT_LINUX_SLL2 headers
pcap/socket.h	    - IP sockets support for various OSes
pcap/usb.h	    - public definition of DLT_USB header
pcap/vlan.h	    - VLAN-specific definitions
pcap-airpcap.c	    - AirPcap device capture support
pcap-airpcap.h	    - AirPcap device capture support
pcap-bpf.c	    - BSD Packet Filter support
pcap-bpf.h	    - header for backwards compatibility
pcap-bt-linux.c	    - Bluetooth capture support for Linux
pcap-bt-linux.h	    - Bluetooth capture support for Linux
pcap-bt-monitor-linux.c - Bluetooth monitor capture support for Linux
pcap-bt-monitor-linux.h - Bluetooth monitor capture support for Linux
pcap-common.c	    - common code for pcap and pcapng files
pcap-common.h	    - common code for pcap and pcapng files
pcap-dag.c	    - Endace DAG device capture support
pcap-dag.h	    - Endace DAG device capture support
pcap-dbus.c	    - D-Bus capture support
pcap-dbus.h	    - D-Bus capture support
pcap-dlpi.c	    - Data Link Provider Interface support
pcap-dos.c	    - MS-DOS capture support
pcap-dos.h	    - headers for MS-DOS capture support
pcap-dpdk.c	    - DPDK device support
pcap-dpdk.h	    - DPDK device support
pcap-enet.c	    - enet support
pcap-hurd.c	    - GNU Hurd support
pcap-int.h	    - internal libpcap definitions
pcap-libdlpi.c	    - Data Link Provider Interface support for systems with libdlpi
pcap-linux.c	    - Linux packet socket support
pcap-namedb.h	    - header for backwards compatibility
pcap-netfilter-linux.c - Linux netfilter support
pcap-netfilter-linux.h - Linux netfilter support
pcap-netmap.c	    - netmap support
pcap-netmap.h	    - netmap support
pcap-nit.c	    - SunOS Network Interface Tap support
pcap-npf.c	    - Npcap capture support
pcap-null.c	    - dummy monitor support (allows offline use of libpcap)
pcap-pf.c	    - Ultrix and Digital/Tru64 UNIX Packet Filter support
pcap-rdmasniff.c    - RDMA/InfiniBand capture support
pcap-rdmasniff.h    - RDMA/InfiniBand capture support
pcap-rpcap.c	    - RPCAP protocol capture support
pcap-rpcap.h	    - RPCAP protocol capture support
pcap-septel.c       - Intel/Septel device capture support
pcap-septel.h       - Intel/Septel device capture support
pcap-sita.c	    - SITA device capture support
pcap-sita.h	    - SITA device capture support
pcap-sita.html	    - SITA device capture documentation
pcap-snf.c	    - Myricom SNF device capture support
pcap-snf.h	    - Myricom SNF device capture support
pcap-snit.c	    - SunOS 4.x STREAMS-based Network Interface Tap support
pcap-snoop.c	    - IRIX Snoop network monitoring support
pcap-tc.c	    - TurboCap device capture support
pcap-tc.h	    - TurboCap device capture support
pcap-types.h	    - header for OS-specific type includes
pcap-usb-linux.c    - USB capture support for Linux
pcap-usb-linux.h    - USB capture support for Linux
pcap-usb-linux-common.c - Linux USB common routines
pcap-usb-linux-common.h - Linux USB common prototypes
pcap-util.c	    - common code for various files
pcap-util.h	    - common code for various files
pcap.3pcap	    - manual entry for the library
pcap.c		    - pcap utility routines
pcap.h		    - header for backwards compatibility
pcap_*.3pcap	    - manual entries for library functions   - manual entry for filter syntax - manual entry for link-layer header types
ppp.h		    - Point to Point Protocol definitions
rpcap-protocol.c    - RPCAP client/server common routines
rpcap-protocol.h    - RPCAP client/server common prototypes
savefile.c	    - offline support
scanner.l	    - filter string scanner
sf-pcap.c	    - routines for .pcap savefiles
sf-pcap.h	    - prototypes for .pcap savefiles
sf-pcapng.c	    - routines for .pcapng savefiles
sf-pcapng.h	    - prototypes for .pcapng savefiles
sockutils.c	    - socket and name lookup API routines
sockutils.h	    - socket and name lookup API prototypes
sslutils.c	    - OpenSSL interface routines
sslutils.h	    - OpenSSL interface prototypes
sunatmpos.h	    - definitions for SunATM capturing
varattrs.h	    - variable attribute macros