Introduces new tags with hostname:

- `<fq-hostname>` - fully-qualified name of host (the same as `$(hostname -f)`)
- `<sh-hostname>` - short hostname (the same as `$(uname -n)`)

Execution of `uname -n` replaced in all mail actions with most interesting fully-qualified `<fq-hostname>`.

config/action.d/mail-buffered.conf

@@ -17,7 +17,7 @@ actionstart = printf %%b "Hi,\n
               The jail <name> has been started successfully.\n
               Output will be buffered until <lines> lines are available.\n
               Regards,\n
-              Fail2Ban"|mail -s "[Fail2Ban] <name>: started on `uname -n`" <dest>
+              Fail2Ban"|mail -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
 
 # Option:  actionstop
 # Notes.:  command executed once at the end of Fail2Ban
@@ -28,13 +28,13 @@ actionstop = if [ -f <tmpfile> ]; then
                  These hosts have been banned by Fail2Ban.\n
                  `cat <tmpfile>`
                  Regards,\n
-                 Fail2Ban"|mail -s "[Fail2Ban] <name>: Summary from `uname -n`" <dest>
+                 Fail2Ban"|mail -s "[Fail2Ban] <name>: Summary from <fq-hostname>" <dest>
                  rm <tmpfile>
              fi
              printf %%b "Hi,\n
              The jail <name> has been stopped.\n
              Regards,\n
-             Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on `uname -n`" <dest>
+             Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
 
 # Option:  actioncheck
 # Notes.:  command executed once before each actionban command

config/action.d/mail-whois-lines.conf

@@ -21,7 +21,7 @@ norestored = 1
 actionstart = printf %%b "Hi,\n
               The jail <name> has been started successfully.\n
               Regards,\n
-              Fail2Ban" | <mailcmd> "[Fail2Ban] <name>: started on `uname -n`" <dest>
+              Fail2Ban" | <mailcmd> "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
 
 # Option:  actionstop
 # Notes.:  command executed once at the end of Fail2Ban
@@ -30,7 +30,7 @@ actionstart = printf %%b "Hi,\n
 actionstop = printf %%b "Hi,\n
              The jail <name> has been stopped.\n
              Regards,\n
-             Fail2Ban" | <mailcmd> "[Fail2Ban] <name>: stopped on `uname -n`" <dest>
+             Fail2Ban" | <mailcmd> "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
 
 # Option:  actioncheck
 # Notes.:  command executed once before each actionban command
@@ -56,7 +56,7 @@ _ban_mail_content = ( printf %%b "Hi,\n
             Regards,\n
             Fail2Ban" )
 
-actionban = %(_ban_mail_content)s | <mailcmd> "[Fail2Ban] <name>: banned <ip> from  `uname -n`" <dest>
+actionban = %(_ban_mail_content)s | <mailcmd> "[Fail2Ban] <name>: banned <ip> from <fq-hostname>" <dest>
 
 # Option:  actionunban
 # Notes.:  command executed when unbanning an IP. Take care that the

config/action.d/mail-whois.conf

@@ -20,7 +20,7 @@ norestored = 1
 actionstart = printf %%b "Hi,\n
               The jail <name> has been started successfully.\n
               Regards,\n
-              Fail2Ban"|mail -s "[Fail2Ban] <name>: started on `uname -n`" <dest>
+              Fail2Ban"|mail -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
 
 # Option:  actionstop
 # Notes.:  command executed once at the end of Fail2Ban
@@ -29,7 +29,7 @@ actionstart = printf %%b "Hi,\n
 actionstop = printf %%b "Hi,\n
              The jail <name> has been stopped.\n
              Regards,\n
-             Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on `uname -n`" <dest>
+             Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
 
 # Option:  actioncheck
 # Notes.:  command executed once before each actionban command
@@ -49,7 +49,7 @@ actionban = printf %%b "Hi,\n
             Here is more information about <ip> :\n
             `%(_whois_command)s`\n
             Regards,\n
-            Fail2Ban"|mail -s "[Fail2Ban] <name>: banned <ip> from `uname -n`" <dest>
+            Fail2Ban"|mail -s "[Fail2Ban] <name>: banned <ip> from <fq-hostname>" <dest>
 
 # Option:  actionunban
 # Notes.:  command executed when unbanning an IP. Take care that the

config/action.d/mail.conf

@@ -16,7 +16,7 @@ norestored = 1
 actionstart = printf %%b "Hi,\n
               The jail <name> has been started successfully.\n
               Regards,\n
-              Fail2Ban"|mail -s "[Fail2Ban] <name>: started  on `uname -n`" <dest>
+              Fail2Ban"|mail -s "[Fail2Ban] <name>: started  on <fq-hostname>" <dest>
 
 # Option:  actionstop
 # Notes.:  command executed once at the end of Fail2Ban
@@ -25,7 +25,7 @@ actionstart = printf %%b "Hi,\n
 actionstop = printf %%b "Hi,\n
              The jail <name> has been stopped.\n
              Regards,\n
-             Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on `uname -n`" <dest>
+             Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
 
 # Option:  actioncheck
 # Notes.:  command executed once before each actionban command
@@ -43,7 +43,7 @@ actionban = printf %%b "Hi,\n
             The IP <ip> has just been banned by Fail2Ban after
             <failures> attempts against <name>.\n
             Regards,\n
-            Fail2Ban"|mail -s "[Fail2Ban] <name>: banned <ip> from `uname -n`" <dest>
+            Fail2Ban"|mail -s "[Fail2Ban] <name>: banned <ip> from <fq-hostname>" <dest>
 
 # Option:  actionunban
 # Notes.:  command executed when unbanning an IP. Take care that the

config/action.d/sendmail-buffered.conf

@@ -17,7 +17,7 @@ norestored = 1
 # Notes.:  command executed once at the start of Fail2Ban.
 # Values:  CMD
 #
-actionstart = printf %%b "Subject: [Fail2Ban] <name>: started on `uname -n`
+actionstart = printf %%b "Subject: [Fail2Ban] <name>: started on <fq-hostname>
               From: <sendername> <<sender>>
               To: <dest>\n
               Hi,\n
@@ -31,7 +31,7 @@ actionstart = printf %%b "Subject: [Fail2Ban] <name>: started on `uname -n`
 # Values:  CMD
 #
 actionstop = if [ -f <tmpfile> ]; then
-                 printf %%b "Subject: [Fail2Ban] <name>: summary from `uname -n`
+                 printf %%b "Subject: [Fail2Ban] <name>: summary from <fq-hostname>
                  From: <sendername> <<sender>>
                  To: <dest>\n
                  Hi,\n
@@ -41,7 +41,7 @@ actionstop = if [ -f <tmpfile> ]; then
                  Fail2Ban" | /usr/sbin/sendmail -f <sender> <dest>
                  rm <tmpfile>
              fi
-             printf %%b "Subject: [Fail2Ban] <name>: stopped  on `uname -n`
+             printf %%b "Subject: [Fail2Ban] <name>: stopped  on <fq-hostname>
              From: Fail2Ban <<sender>>
              To: <dest>\n
              Hi,\n
@@ -64,7 +64,7 @@ actioncheck =
 actionban = printf %%b "`date`: <ip> (<failures> failures)\n" >> <tmpfile>
             LINE=$( wc -l <tmpfile> | awk '{ print $1 }' )
             if [ $LINE -ge <lines> ]; then
-                printf %%b "Subject: [Fail2Ban] <name>: summary from `uname -n`
+                printf %%b "Subject: [Fail2Ban] <name>: summary from <fq-hostname>
                 From: <sendername> <<sender>>
                 To: <dest>\n
                 Hi,\n

config/action.d/sendmail-common.conf

@@ -14,7 +14,7 @@ after = sendmail-common.local
 # Notes.:  command executed once at the start of Fail2Ban.
 # Values:  CMD
 #
-actionstart = printf %%b "Subject: [Fail2Ban] <name>: started on `uname -n`
+actionstart = printf %%b "Subject: [Fail2Ban] <name>: started on <fq-hostname>
               Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
               From: <sendername> <<sender>>
               To: <dest>\n
@@ -27,7 +27,7 @@ actionstart = printf %%b "Subject: [Fail2Ban] <name>: started on `uname -n`
 # Notes.:  command executed once at the end of Fail2Ban
 # Values:  CMD
 #
-actionstop = printf %%b "Subject: [Fail2Ban] <name>: stopped on `uname -n`
+actionstop = printf %%b "Subject: [Fail2Ban] <name>: stopped on <fq-hostname>
              Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
              From: <sendername> <<sender>>
              To: <dest>\n

config/action.d/sendmail-geoip-lines.conf

@@ -23,7 +23,7 @@ norestored = 1
 # Tags:    See jail.conf(5) man page
 # Values:  CMD
 #
-actionban = ( printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from `uname -n`
+actionban = ( printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
             Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
             From: <sendername> <<sender>>
             To: <dest>\n

config/action.d/sendmail-whois-ipjailmatches.conf

@@ -19,7 +19,7 @@ norestored = 1
 # Tags:    See jail.conf(5) man page
 # Values:  CMD
 #
-actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from `uname -n`
+actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
             Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
             From: <sendername> <<sender>>
             To: <dest>\n

config/action.d/sendmail-whois-ipmatches.conf

@@ -19,7 +19,7 @@ norestored = 1
 # Tags:    See jail.conf(5) man page
 # Values:  CMD
 #
-actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from `uname -n`
+actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
             Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
             From: <sendername> <<sender>>
             To: <dest>\n

config/action.d/sendmail-whois-lines.conf

@@ -20,7 +20,7 @@ norestored = 1
 # Tags:    See jail.conf(5) man page
 # Values:  CMD
 #
-actionban = ( printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from `uname -n`
+actionban = ( printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
             Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
             From: <sendername> <<sender>>
             To: <dest>\n

config/action.d/sendmail-whois-matches.conf

@@ -19,7 +19,7 @@ norestored = 1
 # Tags:    See jail.conf(5) man page
 # Values:  CMD
 #
-actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from `uname -n`
+actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
             Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
             From: <sendername> <<sender>>
             To: <dest>\n

config/action.d/sendmail-whois.conf

@@ -19,7 +19,7 @@ norestored = 1
 # Tags:    See jail.conf(5) man page
 # Values:  CMD
 #
-actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from `uname -n`
+actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
             Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
             From: <sendername> <<sender>>
             To: <dest>\n

config/action.d/sendmail.conf

@@ -19,7 +19,7 @@ norestored = 1
 # Tags:    See jail.conf(5) man page
 # Values:  CMD
 #
-actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from `uname -n`
+actionban = printf %%b "Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
             Date: `LC_ALL=C date +"%%a, %%d %%h %%Y %%T %%z"`
             From: <sendername> <<sender>>
             To: <dest>\n

config/action.d/xarf-login-attack.conf

@@ -46,7 +46,7 @@ actionban = oifs=${IFS}; IFS=.;SEP_IP=( <ip> ); set -- ${SEP_IP}; ADDRESSES=$(di
             FROM=<sender>
             SERVICE=<service>
             FAILURES=<failures>
-            REPORTID=<time>@`uname -n`
+            REPORTID=<time>@<fq-hostname>
             TLP=<tlp>
             PORT=<port>
             DATE=`LC_ALL=C date --date=@<time> +"%%a, %%d %%h %%Y %%T %%z"`
@@ -119,7 +119,7 @@ logpath = /dev/null
 
 # Option:  sender
 # Notes.:  This is the sender that is included in the XARF report
-sender = fail2ban@`uname -n`
+sender = fail2ban@<fq-hostname>
 
 # Option:  port
 # Notes.:  This is the port number that received the login-attack

config/jail.conf

@@ -134,7 +134,7 @@ filter = %(__name__)s
 destemail = root@localhost
 
 # Sender email address used solely for some actions
-sender = root@localhost
+sender = root@<fq-hostname>
 
 # E-mail action. Since 0.8.1 Fail2Ban uses sendmail MTA for the
 # mailing. Change mta configuration parameter to mail if you want to

fail2ban/server/actions.py

@@ -35,6 +35,7 @@ except ImportError:
 	OrderedDict = dict
 
 from .banmanager import BanManager
+from .ipdns import DNSUtils
 from .jailthread import JailThread
 from .action import ActionBase, CommandAction, CallingMap
 from .mytime import MyTime
@@ -306,6 +307,9 @@ class Actions(JailThread, Mapping):
 			"ipjailmatches":	lambda self: "\n".join(self._mi4ip().getMatches()),
 			"ipfailures":			lambda self: self._mi4ip(True).getAttempt(),
 			"ipjailfailures":	lambda self: self._mi4ip().getAttempt(),
+			# system-information:
+			"fq-hostname":	lambda self: DNSUtils.getHostname(fqdn=True),
+			"sh-hostname":	lambda self: DNSUtils.getHostname(fqdn=False)
 		}
 
 		__slots__ = CallingMap.__slots__ + ('__ticket', '__jail', '__mi4ip')

fail2ban/server/ipdns.py

@@ -118,6 +118,27 @@ class DNSUtils:
 
 		return ipList
 
+	@staticmethod
+	def getHostname(fqdn=True):
+		"""Get short hostname or fully-qualified hostname of host self"""
+		# try find cached own hostnames (this tuple-key cannot be used elsewhere):
+		key = ('self','hostname', fqdn)
+		name = DNSUtils.CACHE_ipToName.get(key)
+		# get it using different ways (hostname, fully-qualified or vice versa):
+		if name is None:
+			name = ''
+			for hostname in (
+				(socket.getfqdn, socket.gethostname) if fqdn else (socket.gethostname, socket.getfqdn)
+			):
+				try:
+					name = hostname()
+					break
+				except Exception as e: # pragma: no cover
+					logSys.warning("Retrieving own hostnames failed: %s", e)
+		# cache and return :
+		DNSUtils.CACHE_ipToName.set(key, name)
+		return name
+
 	@staticmethod
 	def getSelfNames():
 		"""Get own host names of self"""