Firewall-Nat-Linux - Netzwerk und Serveradministration: Unterschied zwischen den Versionen

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(15 dazwischenliegende Versionen von 2 Benutzern werden nicht angezeigt)
Zeile 1: Zeile 1:
 +
=Erklärung=
 +
*XX = Platznummer
 +
*Y = Klassensaal
 +
=Hostname=
 +
*hostnamectl set-hostname fw.it2XX.int
 +
 
=Interfaces=
 
=Interfaces=
 
*cat /etc/network/interfaces
 
*cat /etc/network/interfaces
Zeile 9: Zeile 15:
  
 
# The primary network interface
 
# The primary network interface
 +
#WAN
 
auto enp0s3
 
auto enp0s3
 
iface enp0s3 inet static
 
iface enp0s3 inet static
−
  address 192.168.5.1XX/24
+
  address 192.168.Y.2XX/24
−
  gateway 192.168.5.254
+
  gateway 192.168.Y.254
−
  post-up ip route add 10.88.0.0/16 via 192.168.Y.14
+
  post-up ip route add 10.88.0.0/16 via 192.168.Y.88
−
post-up /usr/local/sbin/nat.sh
 
  
 +
 +
#LAN
 
auto enp0s8
 
auto enp0s8
 
iface enp0s8 inet static
 
iface enp0s8 inet static
−
  address 172.16.1XX.1/24
+
  address 172.16.2XX.1/24
  
 +
#DMZ
 
auto enp0s9
 
auto enp0s9
 
iface enp0s9 inet static
 
iface enp0s9 inet static
−
  address 10.88.1XX.1/24
+
  address 10.88.2XX.1/24
−
 
 
  
 +
#SERVERS
 
auto enp0s10
 
auto enp0s10
 
iface enp0s10 inet static
 
iface enp0s10 inet static
−
  address 10.1XX.1.1/24
+
  address 10.2XX.1.1/24
 
</pre>
 
</pre>
 +
 
=Hosts=
 
=Hosts=
 
*cat /etc/hosts
 
*cat /etc/hosts
 
<pre>
 
<pre>
−
127.0.0.1       localhost
+
127.0.0.1       localhost
−
127.0.1.1       fw.it1XX.int fw
+
127.0.1.1       fw.it2XX.int fw
  
 
# The following lines are desirable for IPv6 capable hosts
 
# The following lines are desirable for IPv6 capable hosts
−
::1     localhost ip6-localhost ip6-loopback
+
::1     localhost ip6-localhost ip6-loopback
 
ff02::1 ip6-allnodes
 
ff02::1 ip6-allnodes
 
ff02::2 ip6-allrouters
 
ff02::2 ip6-allrouters
Zeile 42: Zeile 52:
 
=Resolver=
 
=Resolver=
 
*cat /etc/resolv.conf
 
*cat /etc/resolv.conf
−
  search it1XX.int
+
  search it2XX.int
−
  nameserver 192.168.Y.14
+
  nameserver 192.168.Y.88
−
=Nat=
+
=NAT mit nftables=
−
*cat /usr/local/sbin/nat.sh
+
;Datei erstellen, alles was drin ist kann raus
 +
*cat /etc/nftables.conf
 
<pre>
 
<pre>
−
#!/bin/bash
+
#!/usr/sbin/nft -f
−
LAN="172.16.1XX.0/24"
+
 
−
SERVERS="10.1XX.1.0/24"
+
# Variablen
−
DMZ="10.88.1XX.0/24"
+
define LAN = 172.16.2XX.0/24
−
#Nat Regeln flushen
+
define SERVERS = 10.2XX.1.0/24
−
iptables -t nat -F
+
define DMZ = 10.88.2XX.0/24
−
#Nat Regelen setzen
+
 
−
iptables -t nat -A POSTROUTING -s $DMZ -d 192.168.Y.0/24 -j RETURN
+
# Alte Regeln löschen (flush)
−
iptables -t nat -A POSTROUTING -s $DMZ -d 10.88.0.0/16 -j RETURN
+
flush table ip nat
−
iptables -t nat -A POSTROUTING -s $DMZ -o enp0s3 -j MASQUERADE
+
 
−
iptables -t nat -A POSTROUTING -s $LAN -o enp0s3 -j MASQUERADE
+
# NAT-Tabelle erstellen/verwenden
−
iptables -t nat -A POSTROUTING -s $SERVERS -o enp0s3 -j MASQUERADE
+
table ip nat {
 +
    chain postrouting {
 +
        type nat hook postrouting priority 100; policy accept;
 +
       
 +
        # DMZ nach 192.168.Y.0/24 - kein NAT (RETURN)
 +
        ip saddr $DMZ ip daddr 192.168.Y.0/24 return
 +
       
 +
        # DMZ nach 10.88.0.0/16 - kein NAT (RETURN)
 +
        ip saddr $DMZ ip daddr 10.88.0.0/16 return
 +
       
 +
        # DMZ nach außen (enp0s3) - Masquerade
 +
        ip saddr $DMZ oif enp0s3 masquerade
 +
       
 +
        # LAN nach außen - Masquerade
 +
        ip saddr $LAN oif enp0s3 masquerade
 +
       
 +
        # SERVERS nach außen - Masquerade
 +
        ip saddr $SERVERS oif enp0s3 masquerade
 +
    }
 +
}
 
</pre>
 
</pre>
−
*chmod +x /usr/local/sbin/nat.sh
+
;Firewall aktivieren
 +
*systemctl enable nftables --now
 +
 
 
=Forward=
 
=Forward=
−
*echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf
+
*echo "net.ipv4.ip_forward=1" > /etc/sysctl.d/99-ipforward.conf
−
*sysctl -p
+
*sysctl -p /etc/sysctl.d/99-ipforward.conf
 +
 
 +
=Reboot=
 +
*systemctl reboot

Aktuelle Version vom 27. März 2026, 13:27 Uhr

Erklärung

  • XX = Platznummer
  • Y = Klassensaal

Hostname

  • hostnamectl set-hostname fw.it2XX.int

Interfaces

  • cat /etc/network/interfaces
source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
#WAN
auto enp0s3
iface enp0s3 inet static
 address 192.168.Y.2XX/24
 gateway 192.168.Y.254
 post-up ip route add 10.88.0.0/16 via 192.168.Y.88


#LAN
auto enp0s8
iface enp0s8 inet static
 address 172.16.2XX.1/24

#DMZ
auto enp0s9
iface enp0s9 inet static
 address 10.88.2XX.1/24

#SERVERS
auto enp0s10
iface enp0s10 inet static
 address 10.2XX.1.1/24

Hosts

  • cat /etc/hosts
127.0.0.1        localhost
127.0.1.1        fw.it2XX.int fw

# The following lines are desirable for IPv6 capable hosts
::1      localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Resolver

  • cat /etc/resolv.conf
search it2XX.int
nameserver 192.168.Y.88

NAT mit nftables

Datei erstellen, alles was drin ist kann raus
  • cat /etc/nftables.conf
#!/usr/sbin/nft -f

# Variablen
define LAN = 172.16.2XX.0/24
define SERVERS = 10.2XX.1.0/24
define DMZ = 10.88.2XX.0/24

# Alte Regeln löschen (flush)
flush table ip nat

# NAT-Tabelle erstellen/verwenden
table ip nat {
    chain postrouting {
        type nat hook postrouting priority 100; policy accept;
        
        # DMZ nach 192.168.Y.0/24 - kein NAT (RETURN)
        ip saddr $DMZ ip daddr 192.168.Y.0/24 return
        
        # DMZ nach 10.88.0.0/16 - kein NAT (RETURN)
        ip saddr $DMZ ip daddr 10.88.0.0/16 return
        
        # DMZ nach außen (enp0s3) - Masquerade
        ip saddr $DMZ oif enp0s3 masquerade
        
        # LAN nach außen - Masquerade
        ip saddr $LAN oif enp0s3 masquerade
        
        # SERVERS nach außen - Masquerade
        ip saddr $SERVERS oif enp0s3 masquerade
    }
}
Firewall aktivieren
  • systemctl enable nftables --now

Forward

  • echo "net.ipv4.ip_forward=1" > /etc/sysctl.d/99-ipforward.conf
  • sysctl -p /etc/sysctl.d/99-ipforward.conf

Reboot

  • systemctl reboot
Abgerufen von „http://wiki.ixheim.de/index.php?title=Firewall-Nat-Linux_-_Netzwerk_und_Serveradministration&oldid=67861“