NAME
pflog —
packet filter logging
interface
SYNOPSIS
device pflog
DESCRIPTION
Thepflog interface is a 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 when the
pflog module is loaded; further instances can be
created using
ifconfig(8). The pflog module is loaded
automatically if both
pf(4)
and pflogd(8) are enabled.
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 pflog create pflog1 # 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.
BUGS
FreeBSD does not set a process id in the pid field in pfloghdr.