The geoip iptables extension allows you to filter, nat or mangle packets based on the country’s source or destination. This does exactly what the geoip apache module does, or the regular geoip binary, but at the iptables level. I would not go into the details why you would want to use that, but there are many ‘positive’ ways it can be useful… For example myself I use it in a project where we want to serve customized content for different countries. Since this is a high traffic site running on many web servers behind a loadbalanced setup, we prefer to split this at the loadbalancer level and not at apache level, to simplify our setup. We serve customized content to the US based visitors, while for the other countries we serve another international site.

Now this has been working fine for a long time now, using the original geoip module and patch-o-matic-ng method of installation (similar to what is very well described here). Still, this is unmaintained, and starting with kernel 2.6.22 it is no longer working. There is a patch that will make it work with a newer kernel, but if you run iptables 1.4.x this will again fail and even if there are some manual walkarounds this is still not the best solution.

The solution is called Xtables-addons. Xtables-addons is the successor to patch-o-matic-ng. Likewise, it contains extensions that were not, or are not yet, accepted in the main kernel/iptables packages. Xtables-addons is different from patch-o-matic in that you do not have to patch or recompile the kernel, sometimes recompiling iptables is also not needed.
The latest version 1.12 supports: iptables >= 1.4.1 and kernel-source >= 2.6.17.

Read the rest of this entry »

For various reasons, I have to look from time to time at one particular IP and try to find out some information about it. Until I have found out about geoiplookup, this was something like: nslookup to get the reverse of the IP, and then whois to find out more details (maybe also traceroute/mtr, etc.). But now I will always start with geoiplookup as it instantly shows me the location (read country) of the respective IP.

Read the rest of this entry »