IPv6: Difference between revisions
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==Local Unicast== | ==Local Unicast (ULA)== | ||
Users were advised to generate a 40 bits Global ID for their intranets but it is unclear if there a valid use case for it[[https://en.wikipedia.org/wiki/Unique_local_address]]. 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] | <strong>[http://tools.ietf.org/html/rfc4193#section-3.2 Local Unicast Address-format]:</strong> | ||
<table> | <table> | ||
<tr> | <tr> | ||
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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. | 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 14:22, 14 June 2024
- https://ifconfig.co/
- Including CLI-support
- https://test-ipv6.com/
- https://ipv6-test.com/
- Check your IPv6 configuration
- http://ipv6-test.com/validate.php
- Check IPv6 support for websites
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. Currently FC00::/8 is undefined, only FD00::/8 is used |
| FE80::/10 | Link Local Unicast | Link Identification, addresses can be based on the interface MAC address |
| FF00::/8 | Multicast |
Local Unicast (ULA)
Users were advised to generate a 40 bits Global ID for their intranets but it is unclear if there a valid use case for it[[1]]. 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 User defined |
16 bits Local subnet |
64 bits Locally assigned or by dhcp |
| 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:
- 0 => IPv6 is not disabled
- 1 => IPv6 is disabled
Check IPv6 autoconfiguration
cat /proc/sys/net/ipv6/conf/eth0/autoconf- 0 => autoconf is disabled
- 1 => autoconf is enabled
Misc commands
- /sbin/ip -6 addr del <ipv6address>/<prefixlength> dev <interface>
- Remove ipv6 addres from an interface