IPv6 is enabled after disabling it via YaST during or after installation.

This document (7007706) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Desktop 10
SUSE Linux Enterprise Server 10

Situation

During installation of SUSE Linux Enterprise (SLE) IPv6 was disabled during the network configuration step. After completing the installation IPv6 address information still showed up in the output of the `ip addr` command. An example is shown below prefixed by 'inet6':

user@mybox0:~> ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 brd 127.255.255.255 scope host lo
    inet 127.0.0.2/8 brd 127.255.255.255 scope host secondary lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether 00:22:19:0a:95:5f brd ff:ff:ff:ff:ff:ff
    inet6 fe80::222:19ff:fe0a:955f/64 scope link
       valid_lft forever preferred_lft forever
3: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
    link/ether 00:22:19:0a:95:5f brd ff:ff:ff:ff:ff:ff
    inet 151.155.131.254/22 brd 151.155.131.255 scope global br0
    inet6 fe80::222:19ff:fe0a:955f/64 scope link
       valid_lft forever preferred_lft forever

Resolution

Whenever IPv6 is disabled the server must be rebooted for the change to be completed. YaST will be configured to no longer use IPv6 once the system is rebooted but, until then, the configuration and the actual implementation are out of sync.

The reason that IPv6 was enabled even though it was disabled during installation is that the installation automatically configures a system to use IPv6. Unless there is a reboot between when that is disabled and when the administrator checks the system, the system will still have the IPv6 kernel modules loaded from the installation. Any reboot from this time on will result in IPv6 being properly disabled.

Additional Information

OpenSUSE 11.x and SUSE Linux Enterprise 11 have a new prompt in YaST when enabling or disabling IPv6 which has the following text:

Warning: To apply this change a reboot is needed.

Because IPv6 is enabled via a kernel module it is not possible to disable IPv6 without unloading modules which, once IPv6 is enabled, are in use. The way to get these kernel modules to no longer be in use is to unload the kernel (by rebooting the server).

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.