|PFLOGD(8)||System Manager's Manual||PFLOGD(8)|
pflogd — packet
filter logging daemon
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
of tcpdump(8), hopefully
offline in case there are bugs in the packet parsing code of
pflogd closes and then re-opens the log
file when it receives
newsyslog(8) to rotate
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
The options are as follows:
pflogddoes not disassociate from the controlling terminal.
pflogdwill use pflog0.
<net/if_pflog.h>. It can restrict the output to packets logged on a specified interface, a rule number, a reason, a direction, an IP family or an action.
Log specific TCP packets to a different log file with a large snaplen (useful with a “log all” rule to dump complete sessions):
# 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
# tcpdump -n -e -ttt -i pflog0
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
pflogd was written by Can
|May 30, 2017||OpenBSD-6.2|