1.\" $OpenBSD: pflogd.8,v 1.51 2019/08/30 17:51:47 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 $Mdocdate: August 30 2019 $ 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.Bk -words 36.Op Fl \&Dx 37.Op Fl d Ar delay 38.Op Fl f Ar filename 39.Op Fl i Ar interface 40.Op Fl s Ar snaplen 41.Op Ar expression 42.Ek 43.Sh DESCRIPTION 44.Nm 45is a background daemon which reads packets logged by 46.Xr pf 4 47to a 48.Xr pflog 4 49interface, normally 50.Pa pflog0 , 51and writes the packets to a logfile (normally 52.Pa /var/log/pflog ) 53in 54.Xr tcpdump 8 55binary format. 56These logs can be reviewed later using the 57.Fl r 58option of 59.Xr tcpdump 8 , 60hopefully offline in case there are bugs in the packet parsing code of 61.Xr tcpdump 8 . 62.Pp 63.Nm 64closes and then re-opens the log file when it receives 65.Dv SIGHUP , 66permitting 67.Xr newsyslog 8 68to rotate logfiles automatically. 69.Dv SIGALRM 70causes 71.Nm 72to flush the current logfile buffers to the disk, thus making the most 73recent logs available. 74The buffers are also flushed every 75.Ar delay 76seconds. 77.Pp 78If the log file contains data after a restart or a 79.Dv SIGHUP , 80new logs are appended to the existing file. 81If the existing log file was created with a different snaplen, 82.Nm 83temporarily uses the old snaplen to keep the log file consistent. 84.Pp 85.Nm 86tries to preserve the integrity of the log file against I/O errors. 87Furthermore, integrity of an existing log file is verified before 88appending. 89If there is an invalid log file or an I/O error, logging is suspended 90until a 91.Dv SIGHUP 92or a 93.Dv SIGALRM 94is received. 95.Pp 96The options are as follows: 97.Bl -tag -width Ds 98.It Fl D 99Debugging mode. 100.Nm 101does not disassociate from the controlling terminal. 102.It Fl d Ar delay 103Time in seconds to delay between automatic flushes of the file. 104This may be specified with a value between 5 and 3600 seconds. 105If not specified, the default is 60 seconds. 106.It Fl f Ar filename 107Log output filename. 108Default is 109.Pa /var/log/pflog . 110.It Fl i Ar interface 111Specifies the 112.Xr pflog 4 113interface to use. 114By default, 115.Nm 116will use 117.Pa pflog0 . 118.It Fl s Ar snaplen 119Analyze at most the first 120.Ar snaplen 121bytes of data from each packet rather than the default of 160. 122The default of 160 is adequate for IP, ICMP, TCP, and UDP headers but may 123truncate protocol information for other protocols. 124Other file parsers may desire a higher snaplen. 125.It Fl x 126Check the integrity of an existing log file, and return. 127.It Ar expression 128Selects which packets will be dumped, using the regular language of 129.Xr tcpdump 8 . 130Tcpdump has been extended to be able to filter on the pfloghdr 131structure defined in 132.In net/if_pflog.h . 133It can restrict the output 134to packets logged on a specified interface, a rule number, a reason, 135a direction, an IP family or an action. 136.Pp 137.Bl -tag -width "ruleset authpfXXX" -offset 3n -compact 138.It ip 139Address family equals IPv4. 140.It ip6 141Address family equals IPv6. 142.It ifname kue0 143Interface name equals "kue0". 144.It on kue0 145Interface name equals "kue0". 146.It ruleset authpf 147Ruleset name equals "authpf". 148.It rulenum 10 149Rule number equals 10. 150.It reason match 151Reason equals match. 152Also accepts "bad-offset", "fragment", "short", "normalize", 153"memory", "bad-timestamp", "congestion", "ip-option", "proto-cksum", 154"state-mismatch", "state-insert", "state-limit", "src-limit", 155and "synproxy". 156.It action pass 157Action equals pass. 158Also accepts "block" and "match". 159.It inbound 160The direction was inbound. 161.It outbound 162The direction was outbound. 163.El 164.El 165.Sh FILES 166.Bl -tag -width /var/run/pflogd.pid -compact 167.It Pa /var/log/pflog 168Default log file. 169.El 170.Sh EXAMPLES 171Log specific TCP packets to a different log file with a large snaplen 172(useful with a 173.Qq log all 174rule to dump complete sessions): 175.Bd -literal -offset indent 176# pflogd -s 1600 -f suspicious.log port 80 and host evilhost 177.Ed 178.Pp 179Log from another 180.Xr pflog 4 181interface, excluding specific packets: 182.Bd -literal -offset indent 183# pflogd -i pflog3 -f network3.log "not (tcp and port 23)" 184.Ed 185.Pp 186Display binary logs: 187.Bd -literal -offset indent 188# tcpdump -n -e -ttt -r /var/log/pflog 189.Ed 190.Pp 191Display the logs in real time (this does not interfere with the 192operation of 193.Nm ) : 194.Bd -literal -offset indent 195# tcpdump -n -e -ttt -i pflog0 196.Ed 197.Pp 198Display the logs in real time of inbound packets that were blocked on 199the wi0 interface: 200.Bd -literal -offset indent 201# tcpdump -n -e -ttt -i pflog0 inbound and action block and on wi0 202.Ed 203.Sh SEE ALSO 204.Xr pcap_open_live 3 , 205.Xr pf 4 , 206.Xr pflog 4 , 207.Xr pf.conf 5 , 208.Xr newsyslog 8 , 209.Xr tcpdump 8 210.Sh HISTORY 211The 212.Nm 213command appeared in 214.Ox 3.0 . 215.Sh AUTHORS 216.Nm 217was written by 218.An Can Erkin Acar Aq Mt canacar@openbsd.org . 219