NAME
pflog - packet filter logging interface
SYNOPSIS
device pflog
DESCRIPTION
The pflog interface is a pseudo-device which makes visible all packets
logged by the packet filter, pf(4). Logged packets can easily be
monitored in real time by invoking tcpdump(1) on the pflog interface, or
stored to disk using pflogd(8).
The pflog0 interface is created automatically at boot if both pf(4) and
pflogd(8) are enabled; further instances can be created using
ifconfig(8).
Each packet retrieved on this interface has a header associated with it
of length PFLOG_HDRLEN. This header documents the address family,
interface name, rule number, reason, action, and direction of the packet
that was logged. This structure, defined in 〈net/if_pflog.h〉 looks like
struct pfloghdr {
u_int8_t length;
sa_family_t af;
u_int8_t action;
u_int8_t reason;
char ifname[IFNAMSIZ];
char ruleset[PF_RULESET_NAME_SIZE];
u_int32_t rulenr;
u_int32_t subrulenr;
uid_t uid;
pid_t pid;
uid_t rule_uid;
pid_t rule_pid;
u_int8_t dir;
u_int8_t pad[3];
};
EXAMPLES
Create a pflog interface and monitor all packets logged on it:
# ifconfig pflog1 up
# tcpdump -n -e -ttt -i pflog1
SEE ALSO
tcpdump(1) inet(4), inet6(4), netintro(4), pf(4), ifconfig(8), pflogd(8)
HISTORY
The pflog device first appeared in OpenBSD 3.0.