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UFW Firewall
Installation und Status
iptables2 ist eine Firewall Einrichtungen bei Ubuntu oder Debian. Eine vereinfachte Version ist ufw .
sudo apt-get update // Software update starten. sudo -s // root Rechte erlangen, Sie müssendas root Passort eingeben. apt-get install ufw // Startet die Installation von ufw
Mit folgendem Befehlt lässt sich die Einstellungen der Firewall anzeigen lassen.
ufw status // Beispielausgabe: root@HPGen10-1:~# ufw status Status: active To Action From -- ------ ---- OpenSSH ALLOW Anywhere 22/tcp ALLOW Anywhere OpenSSH (v6) ALLOW Anywhere (v6) 22/tcp (v6) ALLOW Anywhere (v6) root@HPGen10-1:~#
Wo wird was gespeichert ?
Die Einstellungen werden in folgenden drei Dateien gespeichern:
- /etc/ufw/before.rules
- /var/lib/ufw/user.rules (oder /lib/ufw/user.rules - in welche auch die in der Kommandozeile definierten Regeln persistiert werden)
- /etc/ufw/after.rules
Diese Dateien lassen sich mit jedem Texteditor wie zum Beispiel nano verwalten. Hier eine Beispielausgabe der Datei: /etc/ufw/before.rules
root@HPGen10-1:~# root@HPGen10-1:~# cat /etc/ufw/before.rules # # rules.before # # Rules that should be run before the ufw command line added rules. Custom # rules should be added to one of these chains: # ufw-before-input # ufw-before-output # ufw-before-forward # # Don't delete these required lines, otherwise there will be errors *filter :ufw-before-input - [0:0] :ufw-before-output - [0:0] :ufw-before-forward - [0:0] :ufw-not-local - [0:0] # End required lines # allow all on loopback -A ufw-before-input -i lo -j ACCEPT -A ufw-before-output -o lo -j ACCEPT # quickly process packets for which we already have a connection -A ufw-before-input -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A ufw-before-output -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A ufw-before-forward -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT # drop INVALID packets (logs these in loglevel medium and higher) -A ufw-before-input -m conntrack --ctstate INVALID -j ufw-logging-deny -A ufw-before-input -m conntrack --ctstate INVALID -j DROP # ok icmp codes for INPUT -A ufw-before-input -p icmp --icmp-type destination-unreachable -j ACCEPT -A ufw-before-input -p icmp --icmp-type time-exceeded -j ACCEPT -A ufw-before-input -p icmp --icmp-type parameter-problem -j ACCEPT -A ufw-before-input -p icmp --icmp-type echo-request -j ACCEPT # ok icmp code for FORWARD -A ufw-before-forward -p icmp --icmp-type destination-unreachable -j ACCEPT -A ufw-before-forward -p icmp --icmp-type time-exceeded -j ACCEPT -A ufw-before-forward -p icmp --icmp-type parameter-problem -j ACCEPT -A ufw-before-forward -p icmp --icmp-type echo-request -j ACCEPT # allow dhcp client to work -A ufw-before-input -p udp --sport 67 --dport 68 -j ACCEPT # # ufw-not-local # -A ufw-before-input -j ufw-not-local # if LOCAL, RETURN -A ufw-not-local -m addrtype --dst-type LOCAL -j RETURN # if MULTICAST, RETURN -A ufw-not-local -m addrtype --dst-type MULTICAST -j RETURN # if BROADCAST, RETURN -A ufw-not-local -m addrtype --dst-type BROADCAST -j RETURN # all other non-local packets are dropped -A ufw-not-local -m limit --limit 3/min --limit-burst 10 -j ufw-logging-deny -A ufw-not-local -j DROP # allow MULTICAST mDNS for service discovery (be sure the MULTICAST line above # is uncommented) -A ufw-before-input -p udp -d 224.0.0.251 --dport 5353 -j ACCEPT # allow MULTICAST UPnP for service discovery (be sure the MULTICAST line above # is uncommented) -A ufw-before-input -p udp -d 239.255.255.250 --dport 1900 -j ACCEPT # don't delete the 'COMMIT' line or these rules won't be processed COMMIT root@HPGen10-1:~#
Hier eine Beispielausgabe der Datei: /etc/ufw/user.rules
root@HPGen10-1:~# root@HPGen10-1:~# cat /etc/ufw/user.rules *filter :ufw-user-input - [0:0] :ufw-user-output - [0:0] :ufw-user-forward - [0:0] :ufw-before-logging-input - [0:0] :ufw-before-logging-output - [0:0] :ufw-before-logging-forward - [0:0] :ufw-user-logging-input - [0:0] :ufw-user-logging-output - [0:0] :ufw-user-logging-forward - [0:0] :ufw-after-logging-input - [0:0] :ufw-after-logging-output - [0:0] :ufw-after-logging-forward - [0:0] :ufw-logging-deny - [0:0] :ufw-logging-allow - [0:0] :ufw-user-limit - [0:0] :ufw-user-limit-accept - [0:0] ### RULES ### ### tuple ### allow tcp 22 0.0.0.0/0 any 0.0.0.0/0 OpenSSH - in -A ufw-user-input -p tcp --dport 22 -j ACCEPT -m comment --comment 'dapp_OpenSSH' ### tuple ### allow tcp 22 0.0.0.0/0 any 0.0.0.0/0 in -A ufw-user-input -p tcp --dport 22 -j ACCEPT ### END RULES ### ### LOGGING ### -A ufw-after-logging-input -j LOG --log-prefix "[UFW BLOCK] " -m limit --limit 3/min --limit-burst 10 -A ufw-after-logging-forward -j LOG --log-prefix "[UFW BLOCK] " -m limit --limit 3/min --limit-burst 10 -I ufw-logging-deny -m conntrack --ctstate INVALID -j RETURN -m limit --limit 3/min --limit-burst 10 -A ufw-logging-deny -j LOG --log-prefix "[UFW BLOCK] " -m limit --limit 3/min --limit-burst 10 -A ufw-logging-allow -j LOG --log-prefix "[UFW ALLOW] " -m limit --limit 3/min --limit-burst 10 ### END LOGGING ### ### RATE LIMITING ### -A ufw-user-limit -m limit --limit 3/minute -j LOG --log-prefix "[UFW LIMIT BLOCK] " -A ufw-user-limit -j REJECT -A ufw-user-limit-accept -j ACCEPT ### END RATE LIMITING ### COMMIT root@HPGen10-1:~#
Hier eine Beispielausgabe der Datei: /etc/ufw/after.rules
root@HPGen10-1:~# root@HPGen10-1:~# cat /etc/ufw/after.rules # # rules.input-after # # Rules that should be run after the ufw command line added rules. Custom # rules should be added to one of these chains: # ufw-after-input # ufw-after-output # ufw-after-forward # # Don't delete these required lines, otherwise there will be errors *filter :ufw-after-input - [0:0] :ufw-after-output - [0:0] :ufw-after-forward - [0:0] # End required lines # don't log noisy services by default -A ufw-after-input -p udp --dport 137 -j ufw-skip-to-policy-input -A ufw-after-input -p udp --dport 138 -j ufw-skip-to-policy-input -A ufw-after-input -p tcp --dport 139 -j ufw-skip-to-policy-input -A ufw-after-input -p tcp --dport 445 -j ufw-skip-to-policy-input -A ufw-after-input -p udp --dport 67 -j ufw-skip-to-policy-input -A ufw-after-input -p udp --dport 68 -j ufw-skip-to-policy-input # don't log noisy broadcast -A ufw-after-input -m addrtype --dst-type BROADCAST -j ufw-skip-to-policy-input # don't delete the 'COMMIT' line or these rules won't be processed COMMIT root@HPGen10-1:~#
Einige Beispielanwendungen
# Listet alle Anwendungen auf die durch die Firewall gelangen soll. ufw app list # Zeigt die Details zu OpenSSH an. ufw app info OpenSSH # Lässt OpenSSH durch die Firewall. ufw allow OpenSSH # Zeigt die Einstellungen an. ufw status # Den Port 32456 über TCP freizugeben ufw 32456/tcp
Dokumentation
Mit folgendem Behfehl lässt sich die Dokumentation von ufw ausgeben
sudo man ufw
root@HPGen10-1:~# ufw --help Usage: ufw COMMAND Commands: enable enables the firewall disable disables the firewall default ARG set default policy logging LEVEL set logging to LEVEL allow ARGS add allow rule deny ARGS add deny rule reject ARGS add reject rule limit ARGS add limit rule delete RULE|NUM delete RULE insert NUM RULE insert RULE at NUM route RULE add route RULE route delete RULE|NUM delete route RULE route insert NUM RULE insert route RULE at NUM reload reload firewall reset reset firewall status show firewall status status numbered show firewall status as numbered list of RULES status verbose show verbose firewall status show ARG show firewall report version display version information Application profile commands: app list list application profiles app info PROFILE show information on PROFILE app update PROFILE update PROFILE app default ARG set default application policy root@HPGen10-1:~#