Provided by: sshguard_2.3.1-1_amd64 bug

NAME

       sshguard-setup - setting up SSHGuard on your system

DESCRIPTION

       To   set  up  SSHGuard,  write  sshguard.conf  and  set  up  the  backend,  if  necessary.
       Configuration options are documented in the sample configuration  file.  A  good  starting
       point is to copy it and make the necessary changes:

       1. Set BACKEND. You may also need to set it up to work with SSHGuard (see BACKENDS).

       2. Set  FILES, LOGREADER, or both. Alternatively, give sshguard a list of files to monitor
          as positional arguments on the command-line. If none of these are  set,  sshguard  will
          read from standard input.

       Use  FILES  to  specify  a space-separated list of log files to monitor.  Use LOGREADER to
       specify a shell command to run to obtain logs. Both settings  are  ignored  if  files  are
       given on the command-line.

       Sample  LOGREADER  commands for journalctl(1) and macOS 10.12+ are available in the sample
       configuration.

OTHER LOGS

   syslog-ng
       For syslog-ng 2.x, add the following lines to syslog-ng.conf:

          # pass only entries with auth+authpriv facilities from programs other than sshguard
          filter sshlogs { facility(auth, authpriv) and not match("sshguard"); };
          # pass to this process with this template (avoids <ID> prefixes)
          destination sshguardproc {
          program("/usr/local/sbin/sshguard"
          template("$DATE $FULLHOST $MESSAGE\n"));
          };
          log { source(src); filter(sshlogs); destination(sshguardproc); };

       For syslog-ng 3.x, add the following lines to syslog-ng.conf:

          # enable 3.x mode
          @version:3.0

          # pass only entries with auth+authpriv facilities from programs other than sshguard
          filter f_sshguard { facility(auth, authpriv) and not program("sshguard"); };
          # pass entries built with this format
          destination sshguard {
          program("/usr/sbin/sshguard"
          template("$DATE $FULLHOST $MSGHDR$MESSAGE\n")
          );
          };
          log { source(src); filter(f_sshguard); destination(sshguard); };

       After restarting syslog-ng, SSHGuard should start as soon as a  log  entry  with  facility
       auth  or  authpriv  arrives.  If  you  are  monitoring  services  other than sshd, add the
       appropriate log facilities to syslog-ng.conf.

   metalog
       Add the following lines to metalog.conf:

          Stuff to protect from brute force attacks :
              # for ssh
              facility = "*"
              program = "sshd"
              # other services ...
              # log to /var/log/sshguard directory
              logdir = "/var/log/sshguard"

       After restarting metalog, log entries will appear in /var/log/sshguard.  Use  log  polling
       to monitor the current log.

BACKENDS

       SSHGuard  can  block  attackers using one of several firewall backends that is selected at
       compile-time.

       WARNING:
          Read the documentation for your firewall. Make sure you fully understand each  rule  or
          command  in  the examples below before using them. They may need to be adjusted to suit
          your particular configuration.

   pf
       SSHGuard adds attackers to table <sshguard>. Create  the  table  and  block  attackers  by
       adding the following lines to pf.conf:

          table <sshguard> persist
          block in proto tcp from <sshguard>

       After reloading the pf configuration, you can inspect the contents of the table using:

          # pfctl -t sshguard -T show

   ipfw
       SSHGuard  creates and adds attackers to table 22. The table can be used to block attackers
       in your ruleset. For example:

          # ipfw add 5000 reset ip from table\(22\) to me

       You can inspect the contents of the table using:

          # ipfw table 22 list

   firewalld
       Blocked attackers are added to two ipsets named sshguard4 and sshguard6.  The  entries  in
       the  ipsets are blocked by default in the default firewall zone. Additional firewall zones
       can be configured using:

          # firewall-cmd --zone=zone-name --permanent \
              --add-rich-rule="rule source ipset=sshguard4 drop"
          # firewall-cmd --zone=zone-name --permanent \
              --add-rich-rule="rule source ipset=sshguard6 drop"

       You can inspect the entries in the two ipsets using:

          # firewall-cmd --permanent --info-ipset=sshguard4
          # firewall-cmd --permanent --info-ipset=sshguard6

   ipset
       Blocked attackers are added to two ipsets  named  sshguard4  and  sshguard6.   Nothing  is
       blocked by default, but can used as a source for iptables and other tools. E.g.:

          # iptables  -I INPUT -m set --match-set sshguard4 src -j DROP
          # ip6tables -I INPUT -m set --match-set sshguard6 src -j DROP

   netfilter/iptables
       Create a chain for SSHGuard:

          # iptables -N sshguard      # for IPv4
          # ip6tables -N sshguard     # for IPv6

       Update  the  INPUT chain to also pass the traffic to the sshguard chain at the very end of
       its processing. Specify in --dport all the ports of services your  sshguard  protects.  If
       you  want  to  prevent  attackers  from  doing  any traffic to the host, remove the option
       completely:

          # block any traffic from abusers
          iptables -A INPUT -j sshguard
          ip6tables -A INPUT -j sshguard

       Or:

          # block abusers only for SSH, FTP, POP, IMAP services (use "multiport" module)
          iptables -A INPUT -m multiport -p tcp --destination-ports 21,22,110,143 -j sshguard
          ip6tables -A INPUT -m multiport -p tcp --destination-ports 21,22,110,143 -j sshguard

       Verify that you have NOT a default allow rule passing all ssh traffic higher in the chain.
       Verify that you have NOT a default deny rule blocking all ssh traffic in your firewall. In
       either case, you already have the skill to adjust your firewall setup.

       Here is a sample ruleset that makes sense:

          iptables -N sshguard
          # block whatever SSHGuard says be bad ...
          iptables -A INPUT -j sshguard
          # enable ssh, dns, http, https
          iptables -A INPUT -p tcp --dport 22 -j ACCEPT
          iptables -A INPUT -p udp --dport 53 -j ACCEPT
          iptables -A INPUT -p tcp --dport 80 -j ACCEPT
          iptables -A INPUT -p tcp --dport 443 -j ACCEPT
          # and block everything else (default deny)
          iptables -P INPUT DROP

       When rebooting, most systems reset the firewall configuration by default. To preserve your
       configuration,  you usually use the iptables-save and iptables-restore utilities. However,
       each Linux variant has its own "right way".

   nftables
       SSHGuard creates tables with a high priority and adds attackers to a set automatically.

       You can inspect the contents of the sets using:

          # nft list set ip sshguard attackers
          # nft list set ip6 sshguard attackers

       Moreover, you can display sshguard's tables with:

          # nft list table ip sshguard
          # nft list table ip6 sshguard

EXAMPLES

       Ignore FILES and monitor these files instead:

          # sshguard /var/log/auth.log /var/log/maillog

SEE ALSO

       sshguard(8)