Blog Entries tagged network
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Norwegian Wifi

Published: 2009-04-16 19:14 UTC. Tags: network

The hotel where I'm staying in Oslo has a very special kind of Wireless Internet. It's the kind where you bring your laptop out in the corridor, connect to the network, and then bring the network with you into your room.

Connecting directly from the room doesn't work, even though there's plenty of signal. Well, at least sometimes, there's plenty of signal. Tonight there is, yesterday night I couldn't see the net.

Must be some norweigan special setup.


Calculating the automatically assigned IPv6 adress given prefix and MAC

Published: 2009-02-04 18:36 UTC. Tags: network ipv6

Today I had the need to calculate the automatically assigned IPv6 adress I knew a host probably had since the network has a router advertisment daemon.

I knew the network prefix and the hardware address (MAC/EUI-48). I suspected ipv6calc could probably do the job, but I had great trouble finding out how. I'm sure the commandline syntax for ipv6calc makes sense once you get used to it..

Anyway, here's how, for my own and your future reference:

ipv6calc --in prefix+mac --action prefixmac2ipv6 2001:aaaa:bb:cccc::/64 AA:BB:CC:DD:EE:FF --out ipv6addr

IPv6 prefix as well as MAC obfuscated to protect the innocent.

Relevant links:


Enabling IPv6 in Dovecot and Postfix

Published: 2008-11-29 20:20 UTC. Tags: linux network ipv6

I realized after some testing that neither Postfix (my MTA), nor Dovecot listened to IPv6 by default. In both cases, enabling IPv6 was easy.

(This is where I found out that my algorithm for getting parts of an entry and showing it on the front page doesn't work that well.. so therefore, this text has been added, as it works as a workaround).


Set the inet_protocols parameter in /etc/postfix/


The default value is ipv4.


Set the listen parameter in /etc/dovecot/dovecot.conf:


At least on Linux, this will make Dovecot listen to both IPv4 and IPv6. Setting the value of listen to *, will make it listen only to IPv4.


My apache server happily picked up the presence of an IPv6 interface after a restart. This is probably due to the fact that I have a the following in my Apache configuration:

0 comments. - now via IPv6

Published: 2008-11-29 19:19 UTC. Tags: world wide web network ipv6

I have been intrigued by IPv6 for a long time. The worldwide challenge of smoothly switching from IPv4 to IPv6 without end-users noting the switch is fascinating.

Getting IPv6 adresses for clients or servers where the IPv4 network provider doesn't provide IPv6 natively is very easy - there are several tunnel brokers. I have two tunnels at SixXS - one to get IPv6 at home, and one to get IPv6 to my Slicehost machine (the one serving you this blog post). DNS AAAA entries have been added, so with IPv6 support on your client, you can now reach via IPv6.

However, IPv4 is still required for access, because the slicehost DNS servers that I'm using are reachable via IPv4 only.

To ensure a high nerd factor of, I have also modified django to add a footer to the end of all pages with a happy message if you're running IPv6 :-).