Slow connection requests under Linux

Hello again. Few posts before I have talked about slow web requests in Firefox running in Linux, namely Mandriva 2010.1. Just to remind what the issue was in short. Firefox when  making connection, staled for few seconds when performing DNS request. The issue turned out to be timeout related, because Firefox tried to resolve domain name with IPV6 first. However when there are no IPV6 routers present in your network, FF would wait until name resolution with IPV6 timeouts before sending resolver packets with IPV4. This was very irritating, but could be resolved with the method I have shown in that previous post.

However after some time I’ve discovered that this issue seems to be not Firefox fault. This has greater extent that can be traced to a possible bug in global name resolver library residing in the system. I’m not sure if this issue occurs in Linux distributions other than Mandriva 2010.1. It’s possible. It seems that each and every application that uses system name resolving library has the same problem with AAAA DNS record request timeout when there are no IPV6 routers present in your network. This is very irritating, because each and every program that needs name resolution is painfully slow when trying to make connection.

There’s a rather simple solution to get rid of the problem entirely. You have to disable IPV6 support in your system entirely. I know this is not the perfect solution, but it works. This is how you can do it.

Edit /etc/modprobe.conf and put in those lines:


alias net-pf-10 off
alias ipv6 off
install ipv6 /bin/true

And that’s all. You should restart your system and problems with slow connection requests are gone. Mind you you’re disabling IPV6 support entirely, so if you’d need it again, you’d have to comment those lines put into /etc/modprobe.conf.

I’m not entirely sure if this is a bug or the architectural design problem of the resolver library in Linux. It’s extremely irritating nevertheless.