pflogd(8)
NAME
pflogd - packet filter logging daemon
SYNOPSIS
pflogd [-Dx] [-d delay] [-f filename] [-s snaplen]
[expression]
DESCRIPTION
- pflogd is a background daemon which reads packets logged by
- pf(4) to the
packet logging interface pflog0 and writes the packets to a - logfile (normally /var/log/pflog) in tcpdump(1) binary format. These
- logs can be
reviewed later using the -r option of tcpdump(1), hopefully - offline in
case there are bugs in the packet parsing code of tcp - dump(1).
- pflogd closes and then re-opens the log file when it re
- ceives 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, logging is suspended until a SIGHUP or a SIGALRM is received.
- The options are as follows:
- -D Debugging mode. pflogd does not disassociate from
- the control
- ling terminal.
- -d delay
- Time in seconds to delay between automatic flushes
- of the file.
This may be specified with a value between 5 and - 3600 seconds.
If not specified, the default is 60 seconds. - -f filename
- Log output filename. Default is /var/log/pflog.
- -s snaplen
- Analyze at most the first snaplen bytes of data from
- each packet
rather than the default of 96. The default of 96 is - adequate for
IP, ICMP, TCP, and UDP headers but may truncate pro - tocol information for other protocols. Other file parsers may
- desire a higher
snaplen. - -x Check the integrity of an existing log file, and re
- turn.
- expression
- Selects which packets will be dumped, using the reg
- ular language
of tcpdump(1).
FILES
- /var/run/pflogd.pid Process ID of the currently running
- pflogd.
/var/log/pflog Default log file.
EXAMPLES
- 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
- 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 out - put to packets
logged on a specified interface, a rule number, a reason, a - direction, an
IP family or an action. - ip Address family equals IPv4.
ip6 Address family equals IPv6.
ifname kue0 Interface name equals "kue0".
on kue0 Interface name equals "kue0".
rulenum 10 Rule number equals 10.
reason match Reason equals match. Also accepts "bad-off - set", "frag
- ment", "bad-timestamp", "short", "normalize"
- and "memory".
- action pass Action equals pass. Also accepts "block".
inbound The direction was inbound.
outbound The direction was outbound. - 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
SEE ALSO
- tcpdump(1), pcap(3), pf(4), pflog(4), pf.conf(5), newsys
- log(8)
HISTORY
The pflogd command appeared in OpenBSD 3.0.
AUTHORS
- Can Erkin Acar
- BSD July 9, 2001