1 .\" Copyright (c) 2015 The DragonFly Project. All rights reserved.
3 .\" This code is derived from software contributed to The DragonFly Project
4 .\" by Matthew Dillon <dillon@backplane.com>
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33 .Dd September 13, 2017
38 .Nd utility to block port 22 on preauth failures
41 .Cd # pf(4) configuration.
46 .Cd table <lockout> persist { }
48 .Cd # and later in /etc/pf.conf - see below
50 .Cd block in quick on $ext_if proto tcp from <lockout> to any port 22
52 .Cd # in /etc/syslog.conf
54 .Cd auth.info;authpriv.info |exec /usr/sbin/sshlockout -pf "lockout"
56 .Cd # in root's crontab
58 .Cd 3 3 * * * pfctl -tlockout -T expire 86400
61 .Cd # ipfw(8) configuration.
63 .Cd ipfw table 0 create
64 .Cd ipfw add deny ip from '<0>' to any
66 .Cd # in /etc/syslog.conf
68 .Cd auth.info;authpriv.info |exec /usr/sbin/sshlockout -ipfwtbl 0
70 .Cd # in root's crontab
72 .Cd 3 3 * * * ipfw -fq table 0 expire 86400
74 This program is generally installed in
76 as a pipe to parse the
78 demons error log in realtime.
79 In addition, a root crontab entry should generally be created to clean
80 out stale entries in the
86 Using expire instead of flush will maintain a rolling window of locked out
92 module must be loaded and running with the table and rules properly
95 This program will monitor the ssh syslog output and keep track of attempts
96 to login to unknown users as well as preauth failures.
97 If 5 attempts fail in any one hour period, a permanent entry is added to the
102 for the associated IP address.
103 You still have to add a rule to
107 to block IP addresses listed in this table.
108 The cron entry you create cleans the block list out typically once a day.
110 This program generally limits brute-force attempts to break into a machine
118 note that the table will be filled based on failed ssh connections destined
119 to that particular machine.
120 If the machine is acting as a router you can decide whether you want the
124 rule to lockout that suspect IP to just the machine,
125 or to everything it routes to.
126 We usually recommend an unconditional blocking rule.
128 This program is still a work in progress.
138 utility first appeared in
141 .An Matthew Dillon Aq Mt dillon@backplane.com