pcap_lookupnet(3) pcap_lookupnet(3)
NAME
pcap_lookupnet - find the IPv4 network number and netmask for a device
SYNOPSIS
#include <pcap/pcap.h>
char errbuf[PCAP_ERRBUF_SIZE];
pcap_lookupnet(3) char *device, bpf_u_int32 *netp,
bpf_u_int32 *maskp, char *errbuf);
DESCRIPTION
pcap_lookupnet() is used to determine the IPv4 network number and mask
associated with the network device device. Both netp and maskp are
bpf_u_int32 pointers, on success both values will be set in network
byte order. errbuf is a buffer large enough to hold at least
PCAP_ERRBUF_SIZE chars.
This function is not available on Windows. It supports neither IPv6
nor multiple IPv4 addresses per interface, which obviously is not
practical in modern networks. See pcap_findalldevs(3) for a more
elaborate solution to the problem.
RETURN VALUE
pcap_lookupnet() returns 0 on success and PCAP_ERROR on failure. If
PCAP_ERROR is returned, errbuf is filled in with an appropriate error
message.
SEE ALSO
pcap(3)
31 January 2025 pcap_lookupnet(3)
libpcap 1.11.0 - Generated Tue Sep 15 08:35:16 CDT 2026