doc:appunti:linux:sa:iptables
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| doc:appunti:linux:sa:iptables [2014/04/16 17:35] – [Usare iptables per mitigare o bloccare un DNS Amplification Attack] niccolo | doc:appunti:linux:sa:iptables [2020/11/23 15:28] (current) – [Shorewall and DNAT onto a local host] niccolo | ||
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| A web server is reachable from the internet onto a local host (**192.168.1.5**) via a DNAT rule, local hosts want to use the public address (**130.151.100.69**) to reach the d-natted server. Traffic will be masqueraded by the firewall with its address (**192.168.1.254**) on the local LAN (**eth0**, **192.168.1.0/ | A web server is reachable from the internet onto a local host (**192.168.1.5**) via a DNAT rule, local hosts want to use the public address (**130.151.100.69**) to reach the d-natted server. Traffic will be masqueraded by the firewall with its address (**192.168.1.254**) on the local LAN (**eth0**, **192.168.1.0/ | ||
| - | In '' | + | In **/ |
| < | < | ||
| Line 47: | Line 47: | ||
| </ | </ | ||
| - | In '' | + | For Shorewall 5 we nedd a line in **/ |
| + | |||
| + | < | ||
| + | # | ||
| + | SNAT(192.168.1.254) | ||
| + | </ | ||
| + | |||
| + | Shorewall 4 instead requires a line in **/ | ||
| < | < | ||
| Line 54: | Line 61: | ||
| </ | </ | ||
| - | In '' | + | In **/ |
| < | < | ||
| Line 60: | Line 67: | ||
| # | # | ||
| DNAT | DNAT | ||
| + | DNAT | ||
| </ | </ | ||
| + | |||
| + | Mapping different port from outside to inside is handled only in **/ | ||
| + | ===== Shorewall with router in local LAN ===== | ||
| + | |||
| + | Hosts in LAN#1 may access hosts in LAN#2 by just adding a static route to the **192.168.2.0/ | ||
| + | |||
| + | {{shorewall-router-in-lan.png? | ||
| + | |||
| + | You can instead make **two configurations** on the Shorewall firewall. First of all you add the static route into **/ | ||
| + | |||
| + | < | ||
| + | auto eth1 | ||
| + | iface eth1 inet static | ||
| + | address 192.168.1.1 | ||
| + | netmask 255.255.255.0 | ||
| + | up / | ||
| + | down /sbin/route del -net 192.168.2.0/ | ||
| + | </ | ||
| + | |||
| + | then you have to add the **routeback** option for the **eth1** interfaces in the **/ | ||
| + | |||
| + | < | ||
| + | loc eth1 routeback | ||
| + | </ | ||
| ===== Iptables schema ===== | ===== Iptables schema ===== | ||
| Line 137: | Line 169: | ||
| < | < | ||
| - | iptables -I INPUT -p udp -m string --hex-string ' | + | /sbin/iptables -I INPUT -p udp -m string --hex-string ' |
| - | --algo bm --from 40 --to 56 -j DROP | + | --algo bm --from 40 --to 56 -j DROP -m comment --comment "DROP DNS Q zing.zong.co.ua" |
| </ | </ | ||
| Line 157: | Line 189: | ||
| start) | start) | ||
| iptables -I INPUT $options -j DROP | iptables -I INPUT $options -j DROP | ||
| - | iptables -I INPUT $options -j LOG --log-level debug | + | |
| ;; | ;; | ||
| stop) | stop) | ||
| iptables -D INPUT $options -j DROP | iptables -D INPUT $options -j DROP | ||
| - | iptables -D INPUT $options -j LOG --log-level debug | + | |
| ;; | ;; | ||
| *) | *) | ||
doc/appunti/linux/sa/iptables.1397662546.txt.gz · Last modified: 2014/04/16 17:35 by niccolo