What I used to do for squeeze ( there is a post about it ) does not seem to work well
The system
# cat /etc/issue /etc/debian_version ;uname -a Debian GNU/Linux 7 \n \l 7.5 Linux eudoxus 3.2.0-4-amd64 #1 SMP Debian 3.2.57-3+deb7u1 x86_64 GNU/Linux
Add the following lines to /etc/sysctl.conf
# tail -5 /etc/sysctl.conf net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1 net.ipv6.conf.eth0.disable_ipv6 = 1and
net.ipv6.conf.eth1.disable_ipv6=1 ...
net.ipv6.conf.ifX.disable_ipv6=1
if you have more network interfaces
enable the changes in proc
# sysctl -p net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1 net.ipv6.conf.eth0.disable_ipv6 = 1
Restart networking
# /etc/init.d/networking restart
even though most of the time I am politically incorrect, this time it seems I got it right :)
https://wiki.debian.org/DebianIPv6
disable IPv6 Debian Wheezy