PFLOGD(8) | System Manager's Manual | PFLOGD(8) |
pflogd
—
pflogd |
[-Dx ]
[-d delay]
[-f filename]
[-i interface]
[-p pidfile]
[-s snaplen]
[expression] |
pflogd
is a background daemon which reads packets logged
by pf(4) to a
pflog(4) interface, normally
pflog0, and writes the packets to a logfile (normally
/var/log/pflog) in
tcpdump(8) binary format. These
logs can be reviewed later using the -r
option of
tcpdump(8), hopefully offline
in case there are bugs in the packet parsing code of
tcpdump(8).
pflogd
closes and then re-opens the log
file when it receives SIGHUP
, permitting
newsyslog(8) to rotate
logfiles automatically. SIGALRM
causes
pflogd
to flush the current logfile buffers to the
disk, thus making the most recent logs available. The buffers are also
flushed every delay seconds.
If the log file contains data after a restart or a
SIGHUP
, new logs are appended to the existing file.
If the existing log file was created with a different snaplen,
pflogd
temporarily uses the old snaplen to keep the
log file consistent.
pflogd
tries to preserve the integrity of
the log file against I/O errors. Furthermore, integrity of an existing log
file is verified before appending. If there is an invalid log file or an I/O
error, the log file is moved out of the way and a new one is created. If a
new file cannot be created, logging is suspended until a
SIGHUP
or a SIGALRM
is
received.
The options are as follows:
-D
pflogd
does not disassociate from
the controlling terminal.-d
delay-f
filename-i
interfacepflogd
will use
pflog0.-p
pidfile-s
snaplen-x
pflogd
.# pflogd -s 1600 -f suspicious.log port 80 and host evilhost
Log from another pflog(4) interface, excluding specific packets:
# pflogd -i pflog3 -f network3.log "not (tcp and port 23)"
Display binary logs:
# tcpdump -n -e -ttt -r /var/log/pflog
Display the logs in real time (this does not interfere with the
operation of pflogd
):
# tcpdump -n -e -ttt -i pflog0
Tcpdump has been extended to be able to filter on the pfloghdr structure defined in ⟨net/if_pflog.h⟩. Tcpdump can restrict the output to packets logged on a specified interface, a rule number, a reason, a direction, an IP family or an action.
Display the logs in real time of inbound packets that were blocked on the wi0 interface:
# tcpdump -n -e -ttt -i pflog0 inbound and action block and on wi0
pflogd
command appeared in OpenBSD
3.0.
pflogd
was written by Can Erkin
Acar
<canacar@openbsd.org>.
May 31, 2007 | NetBSD 9.4 |