Debian 6 Squeeze Disable IPv6

slacky · 03-03-2011, 08:06 AM

Hi,

Supposedly you can disable ipv6 in Debian Squeeze with the following:

Code:

echo net.ipv6.conf.all.disable_ipv6=1 > /etc/sysctl.d/disableipv6.conf

However, I found chrony and ntpd will still be shown bound to IPv6 in netstat (I can disable in ntpd's config, but cannot figure out how for chrony). Is the above correct or is there another way (besides compiling a custom kernel) - maybe time servers start earlier in the boot process than when sysctl runs?

Thanks,
slacky

reed9 · 03-03-2011, 11:52 AM

You can always check if the module is loading

Code:

lsmod | grep ipv

You can also try blacklisting the module in /etc/modprobe.d/blacklist.conf
As root

Code:

echo "blacklist ipv6" >> /etc/modprobe.d/blacklist.conf

If something tries to load the module, I don't think this will stop it though. You can send the module off to /bin/true land in that case. This should prevent the module from ever loading.

Code:

echo "install ipv6 /bin/true" >> /etc/modprobe.d/blacklist.conf

slacky · 03-03-2011, 12:49 PM

I think it is compiled in, no ipv6 module loaded nor able to load one, but definitely chrony using:

Code:

# lsmod | grep ipv
nf_conntrack_ipv4       9833  15
nf_defrag_ipv4          1139  1 nf_conntrack_ipv4
nf_conntrack           46535  2 nf_conntrack_ipv4,xt_state

# modprobe ipv6
FATAL: Module ipv6 not found.

# netstat -paunt | grep chrony
udp        0      0 0.0.0.0:123             0.0.0.0:*                           1913/chronyd
udp        0      0 127.0.0.1:323           0.0.0.0:*                           1913/chronyd
udp6       0      0 :::123                  :::*                                1913/chronyd
udp6       0      0 :::323                  :::*                                1913/chronyd