DATAPUISTOKEMISTI

This post is closely related to my  previous  one. Big difference is that in this case company we bought had Lotus Notes based email system that had to be kept running concurrently with new common email platform for several months. Well, actually it is still running to some extent over 4 years later but that's another story.

Few hours ago you got called to meeting with your boss. You were told that company you're working for just bought another firm and everything needs to be integrated ASAP starting with unifying email addresses.

Some time ago I wrote about how to make multiple unreliable Internet connections function like single reliable Internet connection. That was done using OpenVPN and some iptables trickery. This time we're going to do same without OpenVPN and without iptables.

Here's another interesting little known feature of Linux kernel GRE support.

Often it's not necessary to encrypt traffic when tunneling L2 network over L3 in corporate environment. I hear, you say use OpenVPN, tinc, gvpe, n2n etc. Now, did you know that there's easy built-in solution that has been part of Linux kernel since 2.6.29? If you need encryption just use IPsec to protect GRE traffic.

These are kind of "last resort" fixes if all normal ways fail to resolve problem. No guarantees. Worked for me...

It turned out to be just like I suspected , Planet WNAP-7300 (at least with firmware "2.0.3(PL)4") is exactly same device as Zcomax ZCN-1523H-5. Atheros AR7240 rev. 2 at 350MHz, Atheros AR9280 rev 2 5GHz radio, 32MB RAM, 8MB Flash and two 10/100 Ethernet ports. Therefore it works with Zcomax OpenWrt firmware. Bridge performance seems acceptable, around 70Mbit/s real world in bridged mode and 60Mbit/s if OpenWrt is doing NAT. With around 25 meters nearly line-of-sight performance is ~40Mbit/s. All tests uni-directional TCP (FTP/HTTP) with no other traffic than ICMP echo going on at the same time.

Didn't see this documented anywhere so here it is. How to use Finnish dy.fi dynamic DNS service with OpenWrt router.

Host system configuration: Intel Core2Duo 6300 w/VT CentOS 5.7 x64 VMware Workstation 8.0.1

For some reason latest Strongswan version for Ubuntu is still 4.5.1. See below how to compile and package latest 4.6.2dr3. Not pretty, but works for me when testing new version.

As OpenWrt Wiki lacks this particular example (there's other L2TPv3 examples) I guess better I document it somewhere.

Instructions were tested with Ubuntu 11.04.