1 .\" $OpenBSD: pflogd.8,v 1.25 2005/01/02 18:15:02 jmc Exp $
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34 .Nd packet filter logging daemon
44 is a background daemon which reads packets logged by
46 to the packet logging interface
48 and writes the packets to a logfile (normally
53 These logs can be reviewed later using the
57 hopefully offline in case there are bugs in the packet parsing code of
61 closes and then re-opens the log file when it receives
65 to rotate logfiles automatically.
69 to flush the current logfile buffers to the disk, thus making the most
70 recent logs available.
71 The buffers are also flushed every
75 If the log file contains data after a restart or a
77 new logs are appended to the existing file.
78 If the existing log file was created with a different snaplen,
80 temporarily uses the old snaplen to keep the log file consistent.
83 tries to preserve the integrity of the log file against I/O errors.
84 Furthermore, integrity of an existing log file is verified before
86 If there is an invalid log file or an I/O error, logging is suspended until a
92 The options are as follows:
97 does not disassociate from the controlling terminal.
99 Time in seconds to delay between automatic flushes of the file.
100 This may be specified with a value between 5 and 3600 seconds.
101 If not specified, the default is 60 seconds.
107 Analyze at most the first
109 bytes of data from each packet rather than the default of 96.
110 The default of 96 is adequate for IP, ICMP, TCP, and UDP headers but may
111 truncate protocol information for other protocols.
112 Other file parsers may desire a higher snaplen.
114 Check the integrity of an existing log file, and return.
116 Selects which packets will be dumped, using the regular language of
120 .Bl -tag -width /var/run/pflogd.pid -compact
121 .It Pa /var/run/pflogd.pid
122 Process ID of the currently running
124 .It Pa /var/log/pflog
128 Log specific tcp packets to a different log file with a large snaplen
129 (useful with a log-all rule to dump complete sessions):
130 .Bd -literal -offset indent
131 # pflogd -s 1600 -f suspicious.log port 80 and host evilhost
135 .Bd -literal -offset indent
136 # tcpdump -n -e -ttt -r /var/log/pflog
139 Display the logs in real time (this does not interfere with the
142 .Bd -literal -offset indent
143 # tcpdump -n -e -ttt -i pflog0
146 Tcpdump has been extended to be able to filter on the pfloghdr
148 .Aq Ar net/if_pflog.h .
149 Tcpdump can restrict the output
150 to packets logged on a specified interface, a rule number, a reason,
151 a direction, an IP family or an action.
153 .Bl -tag -width "reason match " -compact
155 Address family equals IPv4.
157 Address family equals IPv6.
159 Interface name equals "kue0".
161 Interface name equals "kue0".
163 Rule number equals 10.
166 Also accepts "bad-offset", "fragment", "bad-timestamp", "short",
167 "normalize" and "memory".
170 Also accepts "block".
172 The direction was inbound.
174 The direction was outbound.
177 Display the logs in real time of inbound packets that were blocked on
179 .Bd -literal -offset indent
180 # tcpdump -n -e -ttt -i pflog0 inbound and action block and on wi0