Configuring an Old Server as a Homerouter with Ubuntu and WiFi VPN

Configuring an Old Server as a Home Router (Using Ubuntu)

This article provides a detailed guide on configuring an old server as a home router using Ubuntu. The server will act as a router, providing network connectivity to devices in your home.

Prerequisites

• Basic Linux knowledge
• An old server with minimal hardware requirements (1GB RAM, 2 cores, 20GB storage)
• A stable Internet connection

Steps

1. Install Ubuntu Server

   Follow the official Ubuntu Server installation guide to install Ubuntu Server on your old server.

2. Update and Upgrade

   After installation, open a terminal and run the following commands to update and upgrade the system:

   sudo apt-get update
   sudo apt-get upgrade
   

3. Install Networking Packages

   Install the necessary networking packages:

   sudo apt-get install isc-dhcp-server isc-dhcp-client bind9 dnsmasq iptables
   

4. Configure Network Interfaces

   Edit the /etc/network/interfaces file and configure the network interfaces:

   # Loopback interface
   auto lo
   iface lo inet loopback
   
   # Eth0 - LAN Interface
   auto eth0
   iface eth0 inet static
       address 192.168.1.1
       netmask 255.255.255.0
       gateway 192.168.1.254
   
   # Eth1 - WAN Interface
   auto eth1
   iface eth1 inet dhcp
   

   Save and exit the file.

5. Configure DHCP Server

   Edit the /etc/dhcp/dhcpd.conf file and configure the DHCP range:

   subnet 192.168.1.0 netmask 255.255.255.0 {
       range 192.168.1.100 192.168.1.200;
       option routers 192.168.1.1;
       option domain-name-servers 8.8.8.8, 8.8.4.4;
   }
   

   Save and exit the file. Restart the DHCP server:

   sudo systemctl restart isc-dhcp-server
   

6. Configure DNS Server

   Edit the /etc/bind/named.conf.options file:

   // named.conf.options
   options {
       directory "/var/cache/bind";
   
       // If there is a firewall between you and nameservers you want
       // to talk to, you may need to fix the firewall to allow multiple
       // ports to talk. See http://www.kb.cert.org/vuls/id/800113
   
       // If your ISP provided one or more IP addresses for stable
       // nameservers, you probably want to use them as forwarders.
       // Uncomment the following block, and insert the addresses replacing
       // the all-0's placeholder.
   
       // forwarders {
       //     0.0.0.0;
       // };
   
       //========================================================================
       // If BIND logs error messages about the root key being expired,
       // you will need to update your keys. See https://www.isc.org/bind-keys
       //========================================================================
       dnssec-validation auto;
   
       auth-nxdomain no;    # conform to RFC1035
       listen-on-v6 { any; };
   };
   

   Edit the /etc/bind/db.local file:

   $TTL    604800
   @       IN      SOA     localhost. root.localhost. (
                        1         ; Serial
                     604800         ; Refresh
                      86400         ; Retry
                    2419200         ; Expire
                     604800 )       ; Negative Cache TTL
   ;
   @       IN      NS      localhost.
   @       IN      A       127.0.0.1
   localhost IN      A       127.0.0.1
   

   Save and exit the files. Restart the DNS server:

   sudo systemctl restart bind9
   

7. Configure DNSMasq

   Edit the /etc/dhcp/dhcp-options.conf file:

   option domain-name "yourdomain.com";
   option domain-name-servers 8.8.8.8, 8.8.4.4;
   

   Save and exit the file.

8. Configure Firewall

   Open the /etc/sysctl.conf file and uncomment the following line:

   net.ipv4.ip_forward=1
   

   Save and exit the file. Apply the changes:

   sudo sysctl -p /etc/sysctl.conf
   

   Install iptables-persistent to save the firewall rules:

   sudo apt-get install iptables-persistent
   

   Configure the firewall rules:

   sudo iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
   sudo iptables -A FORWARD -i eth0 -o eth1 -m state --state RELATED,ESTABLISHED -j ACCEPT
   sudo iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
   

   Save the rules:

   sudo service iptables-persistent save
   

9. Reboot

   Reboot the server:

   sudo reboot
   

After rebooting, your old server should act as a home router, providing network connectivity to devices in your home.

References

• Ubuntu Server Installation Guide
• How to Install DHCP Server on Ubuntu 20.04
• How to Install BIND on Ubuntu 20.04
• How to Set Up a Router with Ubuntu Server
• How to Install and Configure iptables-persistent on Ubuntu 20.04