Setting up a gateway on OpenWRT

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ampr-ripd has been compiled for Atheros 71xx

NOTE: To operate a Gateway on AMPRNet, you must have a method of obtaining up-to-date route information. On AMPRNet, a variant of RIP version 2 protocol, named RIP44 is used. RIP version 2 is not the same as RIP44. rip44d is written in the Perl programming language by Heikki Hannikainen, OH7LZB. ampr-ripd is written in C by YO2LOJ. The routing table is relatively small, so the performance or memory consumption of this daemon isn't very critical. ampr-ripd is used in this instance, so no other prerequisite software is required to run the RIP44 daemon.

  • You must have access to a binary executable of ampr-ripd that is compatible with the CPU in your OpenWRT device (e.g. i386, i586, x86_64, MIPS, PPC, etc.). If you do not, you must compile ampr-ripd yourself, or install the packages necessary to run rip44d.



NOTE: These instructions assume first that you have been assigned AMPRNet IP address allocations that are properly assigned and configured to your account in the Portal. Next, that you intend to configure your OpenWRT-based (version 14.07 or greater) AMPRNet Gateway to be a stateful firewall for your AMPRNet allocations (i.e. enabling connection tracking). If you prefer to forward all traffic to your allocated AMPRNet IP addresses, you may follow these instructions; but configure your Firewall Zones to forward all traffic to/from AMPRLAN to AMPRWAN. These instructions configure your AMPRNet Tunnel and AMPRNet Local Interfaces in their own virtual routing and forwarding instance; and places all local AMPRNet allocations in the main routing instance (you must provide routing rules for your local AMPR subnets to reach local subnets, if you desire). Since the OpenWRT Kernel is aware that your AMPRNet allocations exist locally (and are populated on the MAIN ROUTING TABLE), you must provide routing rules for AMPRLAN to reach these local subnets, or omit those rules (not permitting your AMPRLAN to route to your local subnets). Lastly, it assumes that the user can navigate the default OpenWRT LuCI web-based graphical user interface locally (and that they are using a device capable of having the package installed), are familiar with the chmod command, and/or familiar with entering OpenWRT UCI (Unified Configuration Interface) commands by serial console or SSH.


  • kmod-ipip
  • ip-full
  • ampr-ripd to /etc/config/ (always run RIP44 software in console mode FIRST after installation to verify execution and obtain the password, the execution of the file is commented-out below)
  • diffutils (optional for dynamic IP filtering)
  • (optional) dynamic firewall script to /etc/config/ (see the iptables section of the Firewalls wiki)
  • the following to System > Startup > Local Startup:
ip tunnel add tunl0
ip tunnel change tunl0 mode ipip ttl 64 pmtudisc
ip link set tunl0 mtu 1480 up
ip route add default dev tunl0 via <AMPRGW> onlink proto 44 table 44
# This directory is not persistent on OpenWRT, it must be made on boot for dynamic filtering
mkdir /var/lib/ampr-ripd
# A blank bootstrap file must be created at /etc/config/encap.txt for this to work
# after which, you may run ampr-ripd to populate it
ln -s /etc/config/encap.txt /tmp/lib/ampr-ripd/encap.txt
# Dynamic filter, script executed by -x argument
# Dynamic filter, -s argument creates encap.txt
# ./etc/config/ampr-ripd -p <PASSWORD> -s -t 44 -a <> -x ./etc/config/ &
#OPTIONAL LAN ### ip rule add from <> to <> table main priority 22
ip rule add to <> table main priority 44
###Add this after you create the AMPRLAN bridge, this ensures all traffic from AMPRLAN uses table 44
ip rule add dev br-amprlan table 44 priority 45
### This ensures all traffic received on tunl0 uses table 44
ip rule add dev tunl0 table 44 priority 46
### You must add an IP rule for all 44net IPs residing on the device
ip rule add from <> table 44 priority 47
## Allows traceroute to respond using 44net IP of tunl0 or br-amprlan ##
echo 1 > /proc/sys/net/ipv4/icmp_errors_use_inbound_ifaddr
  • reboot
  • an unmanaged interface instance for tunl0 (AMPRWAN) (set to not bring up on boot), adding it to its own firewall zone using Input: Drop (or Reject), Output: Drop (or Reject) and Forward: Drop (or Reject). Be sure to enable connection tracking if you will not masquerade
  • an interface instance for a new VLAN and bridge (AMPRLAN), add it to its own firewall zone using Input: Accept (if you wish for you AMPRLAN devices to reach the router), Output: Accept and Forward: Drop (or Reject). Assign an IP from your allocation to this interface, you will configure this IP on your devices as the Default Route/Gateway address.
  • reboot
  • Permit forwarding from AMPRLAN to AMPRWAN and WAN (you must masquerade this traffic when using WAN)
  • Permit forwarding from LAN to AMPRLAN (as desired, NOTE: you must make an IP Rule for the AMPRLAN to use the LAN's route on the Main Routing Table)
  • Create Traffic Input rule to allow IPv4 IPENCAP (IP protocol type 4) from Any IP on WAN to any IP on Router (or specify WAN IP if statically assigned)
  • Create Traffic Input rule to allow IPv4 udp/520 from in AMPRWAN to at port udp/520 IP on Router
  • Create Traffic Forward rules for any inbound services (as desired)
  • the VLAN to any switch/trunk ports (as desired)
  • make ampr-ripd and executable using chmod +x
  • test ampr-ripd in console using the -d argument
  • add password to the Local Startup entry and uncomment ampr-ripd line
  • reboot