1.\" $OpenBSD: pflogd.8,v 1.24 2004/01/16 10:45:49 jmc 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.Dd July 9, 2001 28.Dt PFLOGD 8 29.Os 30.Sh NAME 31.Nm pflogd 32.Nd packet filter logging daemon 33.Sh SYNOPSIS 34.Nm pflogd 35.Op Fl Dx 36.Op Fl d Ar delay 37.Op Fl f Ar filename 38.Op Fl s Ar snaplen 39.Op Ar expression 40.Sh DESCRIPTION 41.Nm 42is a background daemon which reads packets logged by 43.Xr pf 4 44to the packet logging interface 45.Pa pflog0 46and writes the packets to a logfile (normally 47.Pa /var/log/pflog ) 48in 49.Xr tcpdump 8 50binary format. 51These logs can be reviewed later using the 52.Fl r 53option of 54.Xr tcpdump 8 , 55hopefully offline in case there are bugs in the packet parsing code of 56.Xr tcpdump 8 . 57.Pp 58.Nm 59closes and then re-opens the log file when it receives 60.Dv SIGHUP , 61permitting 62.Xr newsyslog 8 63to rotate logfiles automatically. 64.Dv SIGALRM 65causes 66.Nm 67to flush the current logfile buffers to the disk, thus making the most 68recent logs available. 69The buffers are also flushed every 70.Ar delay 71seconds. 72.Pp 73If the log file contains data after a restart or a 74.Dv SIGHUP , 75new logs are appended to the existing file. 76If the existing log file was created with a different snaplen, 77.Nm 78temporarily uses the old snaplen to keep the log file consistent. 79.Pp 80.Nm 81tries to preserve the integrity of the log file against I/O errors. 82Furthermore, integrity of an existing log file is verified before 83appending. 84If there is an invalid log file or an I/O error, logging is suspended until a 85.Dv SIGHUP 86or a 87.Dv SIGALRM 88is received. 89.Pp 90The options are as follows: 91.Bl -tag -width Ds 92.It Fl D 93Debugging mode. 94.Nm 95does not disassociate from the controlling terminal. 96.It Fl d Ar delay 97Time in seconds to delay between automatic flushes of the file. 98This may be specified with a value between 5 and 3600 seconds. 99If not specified, the default is 60 seconds. 100.It Fl f Ar filename 101Log output filename. 102Default is 103.Pa /var/log/pflog . 104.It Fl s Ar snaplen 105Analyze at most the first 106.Ar snaplen 107bytes of data from each packet rather than the default of 96. 108The default of 96 is adequate for IP, ICMP, TCP, and UDP headers but may 109truncate protocol information for other protocols. 110Other file parsers may desire a higher snaplen. 111.It Fl x 112Check the integrity of an existing log file, and return. 113.It Ar expression 114Selects which packets will be dumped, using the regular language of 115.Xr tcpdump 8 . 116.El 117.Sh FILES 118.Bl -tag -width /var/run/pflogd.pid -compact 119.It Pa /var/run/pflogd.pid 120Process ID of the currently running 121.Nm . 122.It Pa /var/log/pflog 123Default log file. 124.El 125.Sh EXAMPLES 126Log specific tcp packets to a different log file with a large snaplen 127(useful with a log-all rule to dump complete sessions): 128.Bd -literal -offset indent 129# pflogd -s 1600 -f suspicious.log port 80 and host evilhost 130.Ed 131.Pp 132Display binary logs: 133.Bd -literal -offset indent 134# tcpdump -n -e -ttt -r /var/log/pflog 135.Ed 136.Pp 137Display the logs in real time (this does not interfere with the 138operation of 139.Nm ) : 140.Bd -literal -offset indent 141# tcpdump -n -e -ttt -i pflog0 142.Ed 143.Pp 144Tcpdump has been extended to be able to filter on the pfloghdr 145structure defined in 146.Aq Ar net/if_pflog.h . 147Tcpdump can restrict the output 148to packets logged on a specified interface, a rule number, a reason, 149a direction, an IP family or an action. 150.Pp 151.Bl -tag -width "reason match " -compact 152.It ip 153Address family equals IPv4. 154.It ip6 155Address family equals IPv6. 156.It ifname kue0 157Interface name equals "kue0". 158.It on kue0 159Interface name equals "kue0". 160.It rulenum 10 161Rule number equals 10. 162.It reason match 163Reason equals match. 164Also accepts "bad-offset", "fragment", "short", "normalize" and "memory". 165.It action pass 166Action equals pass. 167Also accepts "block". 168.It inbound 169The direction was inbound. 170.It outbound 171The direction was outbound. 172.El 173.Pp 174Display the logs in real time of inbound packets that were blocked on 175the wi0 interface: 176.Bd -literal -offset indent 177# tcpdump -n -e -ttt -i pflog0 inbound and action block and on wi0 178.Ed 179.Sh SEE ALSO 180.Xr pcap 3 , 181.Xr pf 4 , 182.Xr pflog 4 , 183.Xr pf.conf 5 , 184.Xr newsyslog 8 , 185.Xr tcpdump 8 186.Sh HISTORY 187The 188.Nm 189command appeared in 190.Ox 3.0 . 191.Sh AUTHORS 192Can Erkin Acar 193