# IPv6 (正體中文)

Summary help replacing me
This article covers IPv6, and basics of configuring different IPv6 related things like static IP adresses.
Related
IPv6 - Tunnel Broker Setup

In Arch Linux, IPv6 is enabled by default. If you are looking for information regarding IPv6 tunnels, you may want to look at IPv6 - Tunnel Broker Setup.

## Privacy Extensions

To enable Privacy Extensions for Stateless Address Autoconfiguration in IPv6 according to RFC 4941, reproduce the following steps:

Add these lines to `/etc/sysctl.d/40-privacy-extension.conf`::

    # Enable IPv6 Privacy Extensions
    net.ipv6.conf.all.use_tempaddr = 2
    net.ipv6.conf.default.use_tempaddr = 2
    net.ipv6.conf.<nic0>.use_tempaddr = 2
    ...
    net.ipv6.conf.<nicN>.use_tempaddr = 2

Where <nic0> to <nicN> are your nic's (the "all" or "default" parameters do not apply to nic's that already exist when the sysctl settings are applied).

After a reboot, at the latest, Privacy Extensions should be enabled.

## Neighbor Discovery

Pinging the multicast address `ff02::1` results in all hosts in link-local scope responding. An interface has to be specified. With a ping to the multicast address `ff02::2` only routers will respond.

    $ ping6 ff02::1%eth0

If you add an option `-I <your-global-ipv6>`, link-local hosts will respond with their link-global scope addresses. The interface can be omitted in this case.

    $ ping6 -I 2001:4f8:fff6::21 ff02::1

## Static Address

Sometime using static address can improve security. For example, if your local router uses Neighbor Discovery or radvd (RFC 2461), your interface will automatically be assigned an address based its MAC address (using IPv6's Stateless Autoconfiguration). This may be less than ideal for security since it allows a system to be tracked even if the network portion of the IP address changes.

To assign a static address (for example `2001:470:1000:1000::5/64`):

Add your static IP using `netcfg`. You can load them at startup by specifying your `netcfg` profiles in the `NETWORKS` section of `/etc/rc.conf`:

`/etc/network.d/eth0`

    CONNECTION='ethernet'
    DESCRIPTION='ipv6+ipv4 eth0'
    INTERFACE='eth0'

    IP=static
    ADDR=192.168.1.5
    NETMASK=24
    ROUTES=
    GATEWAY=192.168.1.1

    IP6=static
    ADDR6=(2001:470:1000:1000::5/64)
    GATEWAY6=2001:470:1000:1000::1

`/etc/rc.conf`

    NETWORKS=(eth0)

Finally `DAEMONS` section should contain "net-profiles" instead of the deprecated "network". See Netcfg for more information.

## Disable IPv6

Note: The Arch kernel has IPv6 support built in directly [1], therefore a module cannot be blacklisted.

### Disable functionality

Adding `ipv6.disable=1` to the kernel line disables the whole IPv6 stack, which is likely what you want if you are experiencing issues. See Kernel parameters for more information.

Alternatively, adding `ipv6.disable_ipv6=1` instead will keep the IPv6 stack functional but will not assign IPv6 addresses to any of your network devices.

One can also avoid assigning IPv6 addresses to specific network interfaces by adding the following sysctl config to `/etc/sysctl.d/ipv6.conf`:

    # Disable IPv6
    net.ipv6.conf.all.disable_ipv6 = 1
    net.ipv6.conf.<interface0>.disable_ipv6 = 1
    ...
    net.ipv6.conf.<interfaceN>.disable_ipv6 = 1

Note that you must list all of the targeted interfaces explicitly, as disabling "all" does not apply to interfaces that are already "up" when sysctl settings are applied.

### Other programs

Disabling IPv6 functionality in the kernel does not prevent other programs from trying to use IPv6. In most cases, this is completely harmless, but if you find yourself having issues with that program, you should consult the program's man page(s) for a way to disable that functionality.

For example, dhcpcd will continue to harmlessly attempt to perform IPv6 router solicitation. To disable this, as stated in the dhcpcd.conf man page, add the following to `/etc/dhcpcd.conf`:

    noipv6rs

## See also

- IPv6 - kernel.org Documentation

Category:

- Networking (正體中文)