Network setup for RuCTFE 2009

This page explains how to set up a network for RuCTFE 2009. Here is step-by-step guide for Ubuntu 8.04.

Assumptions

• Public NIC - eth0;
• Private NIC - eth1;
• Your team network is 10.N.0.0/16, where N is your team number (see registered teams).

Instructions

1. Install Ubuntu 8.04 Server.

2. Configure your network in /etc/network/interfaces.
   For example:

   auto lo
   iface lo inet loopback
   auto eth0
   iface eth0 inet static
         address 194.226.235.189 # your public ip
         netmask 255.255.255.0   # your netmask
         gateway 194.226.235.250 # your gateway
   
   auto eth1
   iface eth1 inet static
         address 10.N.0.1
         netmask 255.255.0.0
   

3. Install OpenVPN.

   sudo apt-get install openvpn

4. Decrypt and unpack OpenVPN config (should be in your POC's mailbox).

   gpg teamN.tar.gpg && tar xf teamN.tar

5. Copy OpenVPN keys and config to /etc/openvpn.

   sudo cp teamN/* /etc/openvpn

6. Restart OpenVPN.

   invoke-rc.d openvpn restart

7. Now you should have your VPN up and running. Ping 10.0.0.1 to check it .
8. Enable forwarding.
   Uncomment #net.ipv4.ip_forward=1 line in your /etc/sysctl.conf and then run sysctl -p
9. Set up NAT for the networks outside VPN.

   iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

   Put this line to /etc/rc.local to run it automatically during boot.

If you have any problems with network configuration contact us via mailing list or send an email directly to znick.