1 .\" $OpenBSD: pflogd.8,v 1.37 2008/10/22 08:16:49 henning Exp $
3 .\" Copyright (c) 2001 Can Erkin Acar. All rights reserved.
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34 .Nd packet filter logging daemon
47 is a background daemon which reads packets logged by
53 and writes the packets to a logfile (normally
58 These logs can be reviewed later using the
62 hopefully offline in case there are bugs in the packet parsing code of
66 closes and then re-opens the log file when it receives
70 to rotate logfiles automatically.
74 to flush the current logfile buffers to the disk, thus making the most
75 recent logs available.
76 The buffers are also flushed every
80 If the log file contains data after a restart or a
82 new logs are appended to the existing file.
83 If the existing log file was created with a different snaplen,
85 temporarily uses the old snaplen to keep the log file consistent.
88 tries to preserve the integrity of the log file against I/O errors.
89 Furthermore, integrity of an existing log file is verified before
91 If there is an invalid log file or an I/O error, the log file is moved
92 out of the way and a new one is created.
93 If a new file cannot be created, logging is suspended until a
100 will also log the pcap statistics for the
102 interface to syslog when a
106 The options are as follows:
111 does not disassociate from the controlling terminal.
113 Time in seconds to delay between automatic flushes of the file.
114 This may be specified with a value between 5 and 3600 seconds.
115 If not specified, the default is 60 seconds.
120 .It Fl i Ar interface
129 Writes a file containing the process ID of the program to
131 The file name has the form
132 .Ao Ar pidfile Ac Ns .pid .
136 Analyze at most the first
138 bytes of data from each packet rather than the default of 116.
139 The default of 116 is adequate for IP, ICMP, TCP, and UDP headers but may
140 truncate protocol information for other protocols.
141 Other file parsers may desire a higher snaplen.
143 Check the integrity of an existing log file, and return.
145 Selects which packets will be dumped, using the regular language of
149 .Bl -tag -width /var/run/pflogd.pid -compact
150 .It Pa /var/run/pflogd.pid
151 Process ID of the currently running
153 .It Pa /var/log/pflog
157 Log specific tcp packets to a different log file with a large snaplen
158 (useful with a log-all rule to dump complete sessions):
159 .Bd -literal -offset indent
160 # pflogd -s 1600 -f suspicious.log port 80 and host evilhost
165 interface, excluding specific packets:
166 .Bd -literal -offset indent
167 # pflogd -i pflog3 -f network3.log "not (tcp and port 23)"
171 .Bd -literal -offset indent
172 # tcpdump -n -e -ttt -r /var/log/pflog
175 Display the logs in real time (this does not interfere with the
178 .Bd -literal -offset indent
179 # tcpdump -n -e -ttt -i pflog0
182 Tcpdump has been extended to be able to filter on the pfloghdr
184 .Aq Ar net/if_pflog.h .
185 Tcpdump can restrict the output
186 to packets logged on a specified interface, a rule number, a reason,
187 a direction, an IP family or an action.
189 .Bl -tag -width "ruleset authpf " -compact
191 Address family equals IPv4.
193 Address family equals IPv6.
195 Interface name equals "kue0".
197 Interface name equals "kue0".
199 Ruleset name equals "authpf".
201 Rule number equals 10.
204 Also accepts "bad-offset", "fragment", "bad-timestamp", "short",
205 "normalize", "memory", "congestion", "ip-option", "proto-cksum",
206 "state-mismatch", "state-insert", "state-limit", "src-limit",
210 Also accepts "block".
212 The direction was inbound.
214 The direction was outbound.
217 Display the logs in real time of inbound packets that were blocked on
219 .Bd -literal -offset indent
220 # tcpdump -n -e -ttt -i pflog0 inbound and action block and on wi0
237 .An Can Erkin Acar Aq canacar@openbsd.org .