IPv6: Difference between revisions
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;https://ipv6-test.com/ | ;https://ipv6-test.com/ | ||
:Check your IPv6 configuration | :Check your IPv6 configuration | ||
==Address Assignment== | |||
The [http://www.iana.org/assignments/ipv6-address-space IPv6 address assignment] is handled by IANA. Most important prefixes are: | |||
<table class="plain"> | |||
<tr> | |||
<td>2000::/3</td> | |||
<td>Global Unicast</td> | |||
<td>Global scope</td> | |||
</tr> | |||
<tr> | |||
<td>FC00::/7</td> | |||
<td>Unique Local Unicast</td> | |||
<td>Local Unicast. For intranets, not routed, like IPv4 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16</td> | |||
</tr> | |||
<tr> | |||
<td>FE80::/10</td> | |||
<td>Link Local Unicast</td> | |||
<td>Link Identification, addresses often contain the MAC address. MAC 00:16:3e:31:c4:a0 => fe80::2<em><strong>16</strong></em>:<em><strong>3e</strong></em>ff:fe<em><strong>31</strong></em>:<em><strong>c4a0</strong></em>/64</td> | |||
</tr> | |||
<tr> | |||
<td>FF00::/8</td> | |||
<td>Multicast</td> | |||
<td></td> | |||
</tr> | |||
</table> | |||
==Local Unicast== | |||
Uses are advised to generate a 40 bits Global ID for their intranets. It is advised to calculate the Global Id using a specified procedure to maximize the probability of an unique address. | |||
[http://tools.ietf.org/html/rfc4193#section-3.2 Local Unicast Address-format] | |||
<table> | |||
<tr> | |||
<th align=left>Prefix</td> | |||
<th align=left>L</th> | |||
<th align=left>Global ID</th> | |||
<th align=left>Subnet ID</th> | |||
<th align=left>Interface ID</th> | |||
</tr> | |||
<tr> | |||
<td>7 bits<br /> | |||
FC00::/7</td> | |||
<td>1 bit<br /> | |||
Locally assigned</td> | |||
<td>40 bits<br /> | |||
Randomly generated</td> | |||
<td>16 bits<br /> | |||
Local subnet</td> | |||
<td>64 bits<br /> | |||
From MAC address</td> | |||
</tr> | |||
<tr> | |||
<td>1111110</td> | |||
<td>1</td> | |||
<td></td> | |||
<td></td> | |||
<td></td> | |||
</tr> | |||
</table> | |||
The Interface ID is in the so-called ‘Modified EUI-64 Format’. How to go from a MAC address to Modified EUI-64 format is described in appendix A of [href="http://tools.ietf.org/html/rfc4291 RFC 4291].The Routing Advertising Daemon radvd provides ‘Stateless Autoconfiguration’ e.g. by assigning IPv6 addresses and routing information to nodes on the LAN. | |||
==Disable IPv6 on a system== | ==Disable IPv6 on a system== | ||
Revision as of 09:47, 5 April 2020
- https://test-ipv6.com/
- https://ipv6-test.com/
- Check your IPv6 configuration
Address Assignment
The IPv6 address assignment is handled by IANA. Most important prefixes are:
| 2000::/3 | Global Unicast | Global scope |
| FC00::/7 | Unique Local Unicast | Local Unicast. For intranets, not routed, like IPv4 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 |
| FE80::/10 | Link Local Unicast | Link Identification, addresses often contain the MAC address. MAC 00:16:3e:31:c4:a0 => fe80::216:3eff:fe31:c4a0/64 |
| FF00::/8 | Multicast |
Local Unicast
Uses are advised to generate a 40 bits Global ID for their intranets. It is advised to calculate the Global Id using a specified procedure to maximize the probability of an unique address.
| Prefix | L | Global ID | Subnet ID | Interface ID |
|---|---|---|---|---|
| 7 bits FC00::/7 |
1 bit Locally assigned |
40 bits Randomly generated |
16 bits Local subnet |
64 bits From MAC address |
| 1111110 | 1 |
The Interface ID is in the so-called ‘Modified EUI-64 Format’. How to go from a MAC address to Modified EUI-64 format is described in appendix A of [href="http://tools.ietf.org/html/rfc4291 RFC 4291].The Routing Advertising Daemon radvd provides ‘Stateless Autoconfiguration’ e.g. by assigning IPv6 addresses and routing information to nodes on the LAN.
Disable IPv6 on a system
At the end of /etc/sysctl.conf add:
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
- sysctl -p
- Force reload of the kernel parameters as in /etc/sysctl.conf
- cat /proc/sys/net/ipv6/conf/all/disable_ipv6
- Check if IPv6 has been disabled, then the file as 1, else 0