The sys admin's daily grind: Miredo
Exploring the Tunnel

© fckngc, 123RF
The move from IPv4 to IPv6 must be gradual rather than abrupt. After just two minutes of configuration work, Charly leans back and watches his first IPv6 packets pass through a Miredo tunnel.
Network component manufacturers are still spreading the dread tidings: IP addresses are becoming scarce. Stories spread of large access providers buying out smaller ones to get their hands on their IPv4 address pools. If you prefer not to be a victim of the digital famine, you need to switch quickly, says the industry that offers IPv6-capable switches and gateways.
But really, not many access providers can give you native IPv6. In fact, in the context of discussions on IPv6, the word "move" doesn't seem to be all that appropriate. "Co-location" sounds more like it but does tend to remind one of grammar lessons at school. "Dual-tracking" is maybe the best option, because a peaceful coexistence of IPv4 and IPv6 is likely to become the rule, rather than the exception, in the near future.
If you are a customer with an IPv4 provider and would like to add IPv6 to your home network, many tunneling solutions are around that you can try. Configuring them will typically require admin-level skills and is probably beyond the ability of less experienced users, who simply want to explore the field. Teredo solves this problem. The technology, which was developed by Microsoft, sets up an IPv6 tunnel behind a NAT router and automatically distributes the required addresses. Teredo encapsulates the IPv6 payload in v4 UDP datagrams. The Teredo RFC 4380 points out that this is simply an interim solution – other people have been known to refer to it as a "dirty hack."
This Is Not What Problems Look Like
Whatever your opinion, however, Teredo isn't a bad choice for some cautious, initial steps toward IPv6. Setting up Teredo requires virtually no configuration work, and clients are available for any recent operating system. For example, the Linux Miredo [1] client is included with practically any popular distribution. On my Ubuntu lab machine, all I needed to do was type:
apt-get install miredo
to both install the client and start the service. In less than a minute, I had a working IPv6 connection with a prefix of 2001::/32, as defined by the RFC (Figure 1), even though my client resides behind no fewer than two NAT gateways.

Miredo doesn't need a modified kernel; instead, it runs completely in userspace. Although you need to launch Miredo as root to define the required interface parameters, it de-escalates its privileges to nobody after launch. The -u username option lets you specify a user other than nobody. Some distros create a miredo account during the installation.
Finally, a word about security: Whereas NAT routers, which just about every DSL user in the IPv4 world has, put up some kind of protection against undesirable access, IPv6 tears down these barriers. If you are worried about delving into ip6tables, you should at least bind all services suitable for this purpose to localhost (::1).
Infos
- Miredo: http://www.remlab.net/miredo/
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Find SysAdmin Jobs
News
-
KDE Plasma 5.27 Beta is Ready for Testing
The latest beta iteration of the KDE Plasma desktop is now available and includes some important additions and fixes.
-
Netrunner OS 23 Is Now Available
The latest version of this Linux distribution is now based on Debian Bullseye and is ready for installation and finally hits the KDE 5.20 branch of the desktop.
-
New Linux Distribution Built for Gamers
With a Gnome desktop that offers different layouts and a custom kernel, PikaOS is a great option for gamers of all types.
-
System76 Beefs Up Popular Pangolin Laptop
The darling of open-source-powered laptops and desktops will soon drop a new AMD Ryzen 7-powered version of their popular Pangolin laptop.
-
Nobara Project Is a Modified Version of Fedora with User-Friendly Fixes
If you're looking for a version of Fedora that includes third-party and proprietary packages, look no further than the Nobara Project.
-
Gnome 44 Now Has a Release Date
Gnome 44 will be officially released on March 22, 2023.
-
Nitrux 2.6 Available with Kernel 6.1 and a Major Change
The developers of Nitrux have officially released version 2.6 of their Linux distribution with plenty of new features to excite users.
-
Vanilla OS Initial Release Is Now Available
A stock GNOME experience with on-demand immutability finally sees its first production release.
-
Critical Linux Vulnerability Found to Impact SMB Servers
A Linux vulnerability with a CVSS score of 10 has been found to affect SMB servers and can lead to remote code execution.
-
Linux Mint 21.1 Now Available with Plenty of Look and Feel Changes
Vera has arrived and although it is still using kernel 5.15, there are plenty of improvements sure to please everyone.