Network setup for RuCTFE 2011

This page explains how to set up a network for RuCTFE 2011. Here is step-by-step guide for Ubuntu 10.04.

Assumptions

  • Public NIC - eth0;
  • Private NIC - eth1;
  • Your team network is 10.23.N.0/24, where N is your team number (see registered teams).

Instructions

  1. Install Ubuntu 10.04 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 10.23.N.1
      netmask 255.255.255.0
  3. Install OpenVPN. 
    sudo apt-get install openvpn
  4. Unpack OpenVPN config (should be in your POC's mailbox). 
    tar xzf teamN.tar.gz
  5. Copy your private key to teamN directory (which has been extracted from archive), rename it to teamN.key and run 
    ./run-openvpn.sh
  6. Now you should have your VPN up and running. Ping 10.23.0.1 to check it .
  7. Enable forwarding.
    Uncomment #net.ipv4.ip_forward=1 line in your /etc/sysctl.conf and then run sysctl -p
  8. 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.
  9. Set the IP of each team's workstation taking out one from 10.23.N.0/24 pool.
  10. Set the 10.23.N.1 as a gateway on each workstation.
  11. Set the virtual machines NICs bridged to the NIC of the machine hosting the VM.

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