PFLOGD(8)						    BSD System Manager's Manual 						 PFLOGD(8)

NAME

     pflogd -- packet filter logging daemon

SYNOPSIS

     pflogd [-DragonFly] [-d delay] [-f filename] [-i interface] [-p pidfile] [-s snaplen] [expression]

DESCRIPTION

     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 log-
     file (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      Debugging mode.  pflogd does not disassociate from the controlling 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.

     -i interface
	     Specifies the pflog(4) interface to use.  By default, pflogd will use pflog0.

     -p pidfile
	     Writes a file containing the process ID of the program.  The file name has the form /var/run/pidname.pid.	If the option is not
	     given, pidfile defaults to pflogd.

     -s snaplen
	     Analyze at most the first snaplen bytes of data from each packet rather than the default of 116.  The default of 116 is adequate for
	     IP, ICMP, TCP, and UDP headers but may truncate protocol information for other protocols.	Other file parsers may desire a higher
	     snaplen.

     -x      Check the integrity of an existing log file, and return.

     expression
	     Selects which packets will be dumped, using the regular language of tcpdump(8).

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

     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.

     ip 	      Address family equals IPv4.
     ip6	      Address family equals IPv6.
     ifname kue0      Interface name equals "kue0".
     on kue0	      Interface name equals "kue0".
     ruleset authpf   Ruleset name equals "authpf".
     rulenum 10       Rule number equals 10.
     reason match     Reason equals match.  Also accepts "bad-offset", "fragment", "bad-timestamp", "short", "normalize", "memory", "congestion",
		      "ip-option", "proto-cksum", "state-mismatch", "state-insert", "state-limit", "src-limit", and "synproxy".
     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

     pcap(3), pf(4), pflog(4), pf.conf(5), newsyslog(8), tcpdump(8)

HISTORY

     The pflogd command appeared in OpenBSD 3.0.

AUTHORS

     pflogd was written by Can Erkin Acar <canacar@openbsd.org>.

BSD
								   May 31, 2007 							       BSD