Dynamic DNS

If you host your own domain name server and if you want to securely and dynamically update some DNS entries, here is a small howto.

Here is in a nutshell what we are going to do:

1. Create a secret key to securely update the DNS zone
2. Configure a dynamic (sub) zone in your DNS server
3. Create a script to update a DNS entry

[Read more]

6in4 Tunnel

Thanks to company like Hurricane Electric or SixXS it is very easy to connect to IPv6 Internet backbone even if your ISP does not provide native access to IPv6. Those companies provide free access to their tunnel brokers. A tunnel broker is a dual homed router connected to IPv4 Internet backbone on one side and to IPv6 backbone on the other side. The concept is quite simple, you have access to the IPv4 world and you want to access the IPv6 world. You just need to build a 6in4 tunnel from your DSL router or from your PC or actually from whatever IPv4/IPv6 capable you want to the tunnel broker on the IPv4 side and you’ll encapsulate your IPv6 traffic into that tunnel. The broker will decapsulate your IPv6 packets and send them to the IPv6 Internet backbone. The tunnel broker will also advertise your IPv6 range to the backbone in order to allow the traffic to flow back to your 6in4 tunnel. [Read more]

SNMP on Debian

If you want to monitor your servers from a central management station, you’ll probably need to configure an SNMP daemon on your servers. Here is a quick note to show you how easy it is to get started with SNMP on Linux machine (examples are for Debian but should be easy to adapt for other distribution). [Read more]

Dual stack IPv4/IPv6 on FreeBSD

Here is a quick note to show how easy it is to enable a dual IP stack on FreeBSD (and actually on most modern system)… [Read more]

VPS for rent

You need a server connected to Internet? You don’t want a shared server but you don’t want to pay for a dedicated server? exp-NETWORKS can rent you a Virtual Private Server (VPS). A VPS runs its own Linux OS with its own packages, users administration, configuration on a shared hardware. The VPS running on the same hardware are isolated from each other. [Read more]

ClamXav differential update

ClamXav is a free virus checker for Mac OS X. It uses the tried, tested and very popular ClamAV open source antivirus engine as a back end.

The default install of ClamXav does not enable the automatic virus definition update. When a user enables those automatic updates, a ‘good old cron job’ is created for that user. Three minor concerns [Read more]

IPv6 Firewall with Linux

More and more server hoster have configured IPv6 on their network. And most of their Linux based servers come with a basic IPv6 configuration. Even if IPv6 is not used, it is there and widely open as the netfilter/iptables default policy is ACCEPT. [Read more]