Its a POC where I needed a 1:1 NAT using Linux iptables. I used 2 Debian 11 OS for this and here’s the machine IP plans-
- VM-1: IPTables/NAT Router- 123.45.67.5/24, 123.45.67.6/24 and 192.168.10.5/24
- VM-2: Backend Server- 192.168.10.6/24 (this VM’s gateway will be 192.168.10.5
On VM-1
Uninstall nftables and its Dependencies
IPtables is being replaced by nftables starting with Debian 10 Buster. Debian 11 comes with nftables framework. To install iptables first we need uninstall nftables and its dependencies. SSH into your server and run the next commands:
# apt-get remove --auto-remove nftables # apt-get purge nftables
Install IPtables in Debian 11
# apt-get update # apt-get install iptables
Now we can check the iptables status and list rules. For list all the rules we will use option -L.
Run command:
# iptables -L -v
You will see the output:
As you see on the screenshot just installed iptables firewall and it works. But all chains (INPUT, FORWARD, OUTPUT) are set to ACCEPT, and we have no security rules configured.
