1.\" $OpenBSD: pflogd.8,v 1.37 2008/10/22 08:16:49 henning Exp $ 2.\" 3.\" Copyright (c) 2001 Can Erkin Acar. All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. The name of the author may not be used to endorse or promote products 14.\" derived from this software without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd October 22 2008 30.Dt PFLOGD 8 31.Os 32.Sh NAME 33.Nm pflogd 34.Nd packet filter logging daemon 35.Sh SYNOPSIS 36.Nm pflogd 37.Bk -words 38.Op Fl Dx 39.Op Fl d Ar delay 40.Op Fl f Ar filename 41.Op Fl i Ar interface 42.Op Fl s Ar snaplen 43.Op Ar expression 44.Ek 45.Sh DESCRIPTION 46.Nm 47is a background daemon which reads packets logged by 48.Xr pf 4 49to a 50.Xr pflog 4 51interface, normally 52.Pa pflog0 , 53and writes the packets to a logfile (normally 54.Pa /var/log/pflog ) 55in 56.Xr tcpdump 1 57binary format. 58These logs can be reviewed later using the 59.Fl r 60option of 61.Xr tcpdump 1 , 62hopefully offline in case there are bugs in the packet parsing code of 63.Xr tcpdump 1 . 64.Pp 65.Nm 66closes and then re-opens the log file when it receives 67.Dv SIGHUP , 68permitting 69.Xr newsyslog 8 70to rotate logfiles automatically. 71.Dv SIGALRM 72causes 73.Nm 74to flush the current logfile buffers to the disk, thus making the most 75recent logs available. 76The buffers are also flushed every 77.Ar delay 78seconds. 79.Pp 80If the log file contains data after a restart or a 81.Dv SIGHUP , 82new logs are appended to the existing file. 83If the existing log file was created with a different snaplen, 84.Nm 85temporarily uses the old snaplen to keep the log file consistent. 86.Pp 87.Nm 88tries to preserve the integrity of the log file against I/O errors. 89Furthermore, integrity of an existing log file is verified before 90appending. 91If there is an invalid log file or an I/O error, the log file is moved 92out of the way and a new one is created. 93If a new file cannot be created, logging is suspended until a 94.Dv SIGHUP 95or a 96.Dv SIGALRM 97is received. 98.Pp 99.Nm 100will also log the pcap statistics for the 101.Xr pflog 4 102interface to syslog when a 103.Dv SIGUSR1 104is received. 105.Pp 106The options are as follows: 107.Bl -tag -width Ds 108.It Fl D 109Debugging mode. 110.Nm 111does not disassociate from the controlling terminal. 112.It Fl d Ar delay 113Time in seconds to delay between automatic flushes of the file. 114This may be specified with a value between 5 and 3600 seconds. 115If not specified, the default is 60 seconds. 116.It Fl f Ar filename 117Log output filename. 118Default is 119.Pa /var/log/pflog . 120.It Fl i Ar interface 121Specifies the 122.Xr pflog 4 123interface to use. 124By default, 125.Nm 126will use 127.Ar pflog0 . 128Writes a file containing the process ID of the program to 129.Pa /var/run . 130The file name has the form 131The default is 132.Ar pflogd . 133.It Fl s Ar snaplen 134Analyze at most the first 135.Ar snaplen 136bytes of data from each packet rather than the default of 116. 137The default of 116 is adequate for IP, ICMP, TCP, and UDP headers but may 138truncate protocol information for other protocols. 139Other file parsers may desire a higher snaplen. 140.It Fl x 141Check the integrity of an existing log file, and return. 142.It Ar expression 143Selects which packets will be dumped, using the regular language of 144.Xr tcpdump 1 . 145.El 146.Sh FILES 147.Bl -tag -width /var/run/pflogd.pid -compact 148.It Pa /var/run/pflogd.pid 149Process ID of the currently running 150.Nm . 151.It Pa /var/log/pflog 152Default log file. 153.El 154.Sh EXAMPLES 155Log specific tcp packets to a different log file with a large snaplen 156(useful with a log-all rule to dump complete sessions): 157.Bd -literal -offset indent 158# pflogd -s 1600 -f suspicious.log port 80 and host evilhost 159.Ed 160.Pp 161Log from another 162.Xr pflog 4 163interface, excluding specific packets: 164.Bd -literal -offset indent 165# pflogd -i pflog3 -f network3.log "not (tcp and port 23)" 166.Ed 167.Pp 168Display binary logs: 169.Bd -literal -offset indent 170# tcpdump -n -e -ttt -r /var/log/pflog 171.Ed 172.Pp 173Display the logs in real time (this does not interfere with the 174operation of 175.Nm ) : 176.Bd -literal -offset indent 177# tcpdump -n -e -ttt -i pflog0 178.Ed 179.Pp 180Tcpdump has been extended to be able to filter on the pfloghdr 181structure defined in 182.Aq Ar net/if_pflog.h . 183Tcpdump can restrict the output 184to packets logged on a specified interface, a rule number, a reason, 185a direction, an IP family or an action. 186.Pp 187.Bl -tag -width "ruleset authpf " -compact 188.It ip 189Address family equals IPv4. 190.It ip6 191Address family equals IPv6. 192.It ifname kue0 193Interface name equals "kue0". 194.It on kue0 195Interface name equals "kue0". 196.It ruleset authpf 197Ruleset name equals "authpf". 198.It rulenum 10 199Rule number equals 10. 200.It reason match 201Reason equals match. 202Also accepts "bad-offset", "fragment", "bad-timestamp", "short", 203"normalize", "memory", "congestion", "ip-option", "proto-cksum", 204"state-mismatch", "state-insert", "state-limit", "src-limit", 205and "synproxy". 206.It action pass 207Action equals pass. 208Also accepts "block". 209.It inbound 210The direction was inbound. 211.It outbound 212The direction was outbound. 213.El 214.Pp 215Display the logs in real time of inbound packets that were blocked on 216the wi0 interface: 217.Bd -literal -offset indent 218# tcpdump -n -e -ttt -i pflog0 inbound and action block and on wi0 219.Ed 220.Sh SEE ALSO 221.Xr pcap 3 , 222.Xr pf 4 , 223.Xr pflog 4 , 224.Xr pf.conf 5 , 225.Xr newsyslog 8 , 226.Xr tcpdump 1 227.Sh HISTORY 228The 229.Nm 230command appeared in 231.Ox 3.0 . 232.Sh AUTHORS 233.Nm 234was written by 235.An Can Erkin Acar Aq canacar@openbsd.org . 236