Firwall 5105: Unterschied zwischen den Versionen

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Zeile 25: Zeile 25:
 
  address 10.88.TN.1
 
  address 10.88.TN.1
 
</pre>
 
</pre>
 
=Hosts=
 
*cat /etc/hosts
 
<pre>
 
127.0.0.1      localhost
 
127.0.1.1      fw.it1XX.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
 
</pre>
 
=Resolver=
 
*cat /etc/resolv.conf
 
search it1XX.int
 
nameserver 192.168.Y.88
 
=Nat=
 
*cat /usr/local/sbin/nat.sh
 
<pre>
 
#!/bin/bash
 
LAN="172.16.1XX.0/24"
 
SERVERS="10.1XX.1.0/24"
 
DMZ="10.88.1XX.0/24"
 
#Nat Regeln flushen
 
iptables -t nat -F
 
#Nat Regelen setzen
 
iptables -t nat -A POSTROUTING -s $DMZ -d 192.168.Y.0/24 -j RETURN
 
iptables -t nat -A POSTROUTING -s $DMZ -d 10.88.0.0/16 -j RETURN
 
iptables -t nat -A POSTROUTING -s $DMZ -o enp0s3 -j MASQUERADE
 
iptables -t nat -A POSTROUTING -s $LAN -o enp0s3 -j MASQUERADE
 
iptables -t nat -A POSTROUTING -s $SERVERS -o enp0s3 -j MASQUERADE
 
</pre>
 
*chmod +x /usr/local/sbin/nat.sh
 
 
=NAT mit nftables=
 
=NAT mit nftables=
 
<pre>
 
<pre>
Zeile 63: Zeile 30:
  
 
# Variablen
 
# Variablen
define LAN = 172.16.1XX.0/24
+
define LAN = 172.26.XX.0/24
define SERVERS = 10.1XX.1.0/24
+
define DMZ = 10.88.XX.0/24
define DMZ = 10.88.1XX.0/24
 
  
 
# Alte Regeln löschen (flush)
 
# Alte Regeln löschen (flush)
Zeile 87: Zeile 53:
 
         ip saddr $LAN oif enp0s3 masquerade
 
         ip saddr $LAN oif enp0s3 masquerade
 
          
 
          
        # SERVERS nach außen - Masquerade
 
        ip saddr $SERVERS oif enp0s3 masquerade
 
 
     }
 
     }
 
}
 
}
 
</pre>
 
</pre>
=Forward=
+
# IP-Forwarding dauerhaft aktivieren (Modern Way)
*echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf
+
echo "net.ipv4.ip_forward=1" | sudo tee /etc/sysctl.d/99-ip-forward.conf
*sysctl -p
+
 
=Reboot=
+
# Konfiguration ohne Neustart sofort laden
*systemctl reboot
+
sudo sysctl --system
 +
 
 +
# System neu starten (optional zur Verifizierung)
 +
sudo systemctl reboot

Version vom 16. März 2026, 11:34 Uhr

Erklärung

  • XX = Platznummer
  • Y = Klassensaal

Hostname

Grundkonfiguration
  • debian-setup -f fw.it213.int -a 192.168.HS.TN/24 -g 192.168.HS.254. -n 1.1.1.1
  • reboot
Weitere Interfaces
  • cat/etc/network/interfaces
auto lo
iface lo inet loopback

auto enp0s3
iface enp0s3 inet static
 address 192.168.HS.TN/24
 gateway 192.168.HS.254

auto enp0s8
iface enp0s8 inet static
 address 172.26.TN.1/24

auto enp0s9
iface enp0s9 inet static
 address 10.88.TN.1

NAT mit nftables

#!/usr/sbin/nft -f

# Variablen
define LAN = 172.26.XX.0/24
define DMZ = 10.88.XX.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
        
    }
}
  1. IP-Forwarding dauerhaft aktivieren (Modern Way)

echo "net.ipv4.ip_forward=1" | sudo tee /etc/sysctl.d/99-ip-forward.conf

  1. Konfiguration ohne Neustart sofort laden

sudo sysctl --system

  1. System neu starten (optional zur Verifizierung)

sudo systemctl reboot