How to dynamically enable and disable ipv6 on an interface

How to dynamically enable and disable IPv6 on an interface so that it gets link local address when enabled? I have tried:

sysctl net.ipv6.conf.all.disable_ipv6=1 to disable IPv6

and

sysctl net.ipv6.conf.all.disable_ipv6=0 to enable IPv6.

Are there any other ways?

3 Answers

To disable IPv6

$ su -
# nano /etc/sysctl.conf

and add these lines to sysctl.conf file

#disable ipv6
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

Save sysctl.conf file with new config and run the following command to enable the new settings:

# sysctl -p 

Check your system again

$ cat /proc/sys/net/ipv6/conf/all/disable_ipv6

Now you should see “1″ means IPv6 has been disabled on your system.

From

I think your approach is valid as it is. You could use the per-interface settings if you don't want to change settings for every interface, e.g. net.ipv6.conf.eth0.disable_ipv6

I wouldn't recommend touching anything else.

To turn off IPv6 in Ubuntu 11.04

Firstly, On or off, check it out

$ ifconfig -a
eth0 Link encap:Ethernet HWaddr inet addr: Bcast: Mask: **inet6** addr: fe80::210:f3ff:fe21:722a/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:982 errors:0 dropped:0 overruns:0 frame:0 TX packets:943 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:800461 (800.4 KB) TX bytes:144524 (144.5 KB) Interrupt:20 Memory:f7d00000-f7d20000
eth1 Link encap:Ethernet HWaddr UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:16 Memory:f7c00000-f7c20000
lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 **inet6** addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:20 errors:0 dropped:0 overruns:0 frame:0 TX packets:20 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1200 (1.2 KB) TX bytes:1200 (1.2 KB)

Secondly, Turn off, i modified the line as following and patched the grub

$ grep ipv6 /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 quiet splash"
$ update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-2.6.38-11-generic-pae
Found initrd image: /boot/initrd.img-2.6.38-11-generic-pae
Found memtest86+ image: /boot/memtest86+.bin
done