Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have an embedded system built using buildroot. I have had a number of network issues, one of which is that my machine cannot see its gateway despite it being on the same subnet. I have tried using wireshark to analyse what is going on without success so as a last resort, I am considering trying to turn off support for IPv6 as I do not need it (my device doesn't need DNS or anything similar, simply needs to be able to communicate with other local machines on its subnet). I have read that I can turn off IPv6 by editing /etc/modprobe.conf but this file does not exist on my setup. Is there anything else I can do to disable IPv6 or is the only option to build the kernel from scratch without IPv6 support?

share|improve this question
up vote 3 down vote accepted

I agree with Ulrich, that this doesn't sound like an IPv6 problem. However, here's how to disable IPv6.

In /etc/sysctl.conf set the following options:

net.ipv6.conf.all.autoconf = 0
net.ipv6.conf.all.accept_ra = 0
net.ipv6.conf.all.disable_ipv6 = 1

If you don't have /etc/sysctl.conf just create it and add those lines, then reboot.

Alternatively, each of these has an interface in /proc that you can flip (and/or create a script to do this at boot time).

echo 0 > /proc/sys/net/ipv6/conf/all/autoconf
echo 0 > /proc/sys/net/ipv6/conf/all/accept_ra
echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
share|improve this answer
Thanks for your answer. Unfortunately I do not have a sysctl.conf file on my embedded system. I think I will try to recompile the kernel. – mathematician1975 Mar 4 '13 at 9:09
Do you have a sysctl command? – bahamat Mar 8 '13 at 20:52
Yes I have a sysctl command as part of the busybox binary. I can see an option to read from a specified file of which /etc/sysctl.conf is the default. Perhaps I just need to create this file and input the lines you suggest, then run sysctl ? You were right about it not being IPv6 problem though - I simply had incorrect information from the network administrator. – mathematician1975 Mar 22 '13 at 11:35
Yes, you just need to create the file with the parameters you want and reboot. – bahamat Mar 22 '13 at 15:47

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.