Nach 20 Jahren IPv6 (RFC2460 erschien im Dezember 1998) und knapp 40% Verbreitung an Deutschlands Internetzugängen stellt sich IPv6 für die meisten Admins immer noch als Mysterium dar. Teilweise wird sogar von führenden Experten empfohlen IPv6 abzuschalten "weil das nur Probleme macht". Warum das nicht so ist, und warum man sich doch auf die "neue" Welt einlassen sollte erklärt dieser praxisorientierte Vortrag. Der Vortag führt ein in Adresskonzepte, Adressvergabe und -auflösung (SLAAC, DHCPv6, DHCPv6-PD, ND, RDNSS, etc.) und zeigt einen typischen Adressierunsplan auf. Brückentechnologien wie NAT64, DS-lite und Teredo werden vorgestellt und eingeordnet. Die Konfiguration von IPv6 unter Linux wird am Beispiel von iproute2 bzw. Debian Netzwerkkonfiguration sowie sysctls aufgezeigt.

1. IPv6 in 2018
FrOSCon 13 Network Track
Falk Stern, Maximilian Wilhelm
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2. Agenda
1. Who's who
2. History
3. IPv6
1. Addressing
2. Packet Format
3. ICMP, Neighbour Discovery, Autoconfig
4. Transition Technologies
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3. Who's who Falk Stern
Full Stack Infrastructure Engineer
IPv6 fanboy
Runs his own Kubernetes cluster in his basement
Consultant @ Profi Engineering Systems AG
Contact
@wrf42
falk@fourecks.de
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4. Who's who Maximilian Wilhelm
Networker
OpenSource Hacker
Fanboy of
(Debian) Linux
ifupdown2
Occupation:
By day: Senior Infrastructure Architect, Uni Paderborn
By night: Infrastructure Archmage, Freifunk Hochstift
In between: Freelance Solution Architect for hire
Contact
@BarbarossaTM
max@sdn.clinic
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5. Who's who
History
IPv4 allocations have been made
NAT is everywhere, even in your
Fritz!Box
CGN/LSN breaks your applications
Some devices still don't support IPv6
State of the InterNAT
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6. Who's who
History
IPv6 history
Introduced in RFC2460, December 1998
Adressing
Diminishing IPv4 address space
Use of NAT/PAT
Growing routing tables
First deployment was with 6bone, stopped on 6.6.2006
Hurricane Electric, SixXs pushed IPv6 tunnels
Germany has >35% IPv6 adoption per https://google.com/ipv6
Global IPv6 Adoption is at 22%
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7. Who's who
History
IPv6
What's "new"
Different address format
Different header
Stateless autoconfiguration
no need for DHCP
Broadcast replaced by multicast
Global address hierarchy
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8. Who's who
History
IPv6
Address format
Standard form
8 x 16bit hexadecimal
2001:0db8:affe:c0d4:0000:0000:00c0:fffe
Short form
Sequence of 0 replaced by ::, leading 0 can be omitted
2001:db8:affe:c0d4::c0:fffe
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9. Who's who
History
IPv6
Address format
IPv4 compatible addresses
0000:0000:0000:0000:0000:ffff:192.0.2.4
or
::ffff:192.0.2.4
CIDR notation for pre xes
2001:db8:affe:c0d4::/64
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10. Who's who
History
IPv6
Address types
Unicast
Global (everything not specified elsewhere)
unique local (ULA) - FC00::/7
link-local (LLA) - FE80::/10
IPv4 mapped - ::ffff:192.0.2.4
Loopback - ::1/128
unspecified - ::/128
Multicast
FF00::/8
No broadcast
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11. Who's who
History
IPv6
Header format
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12. Who's who
History
IPv6
ICMPv6
Defined in RFC4443
Informational (Type > 127)
Echo Request (128)
Echo Reply (129)
...
Error (Type < 128)
Destination Unreachable (1)
Packet Too Big (2)
Time Exceeded (3)
Parameter Problem (4)
If you really want to filter ICMPv6, please read RFC4890
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13. Who's who
History
IPv6
IPv6 Neighbour Discovery
Protocol over ICMPv6
Router Solicitation / Advertisement
Neighbour Solicitation / Advertisement
Redirect
Replaces ARP and certain ICMPv4 messages
Implemented through Multicast
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14. Who's who
History
IPv6
64-Bit Extended Unique Identifier
First 24, 28 or 36 bit identify the
vendor
Modified EUI-64 is used by IPv6 to
generate an interface identifier
MAC address is split into 24 bit parts,
FFFE inserted in-between
seventh bit from the left is inverted
1st octet 2nd octet 3rd octet 4th octet 5th octet 6th octet
6 octets
or
Organisationally Unique
Identifier (OUI)
Network Interface Controller
(NIC) Specific
3 octets 3 octets
b7 b6 b5 b4 b3 b2 b1 b0
8 bits
0:
1:
unicast
multicast
0:
1:
globally unique (OUI enforced)
locally administered
EUI-64
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15. Who's who
History
IPv6
Stateless Autocon guration (SLAAC)
1. Interface assigns a link-local address w/ interface identifier
2. Interface sends router solicitation
3. Router sends router advertisement, including prefix, default gateway, etc.
4. Interface creates global address from prefix and interface identifier
5. Interface sends a neighbour solicitation for Duplicate Address Detection
Router advertisement can contain:
Prefix
Lifetime
DNS Server
Default Gateway
MTU
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16. Who's who
History
IPv6
Stateful Autocon guration (DHCPv6)
IPv6 can use DHCP to configure all parameters
Required for UEFI netbooting
Only way to configure a nameserver if the router does not support RDNSS
(RFC8106)
Required for Prefix Delegation (DHCPv6-PD)
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17. Who's who
History
IPv6
Stateless Autocon guration with DHCPv6
Address is configured through SLAAC
DNS Server is configured through DHCPv6
Android doesn't support this
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18. Who's who
History
IPv6
Privacy extensions (RFC4941)
As a global IPv6 address can be used to identify a single computer, there is a privacy
issue.
Hosts can generate additional random interface identifiers for outgoing connections.
These addresses expire after a certain amount of time.
A host can have a number of addresses configured at the same time.
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19. Who's who
History
IPv6
Subnetting
Your LAN should have a /64
That's more than 18 quintillion addresses
Deutsche Telekom delegates you a /56
That's 256 times 18 quintillion addresses
A site should use a /48
That's 65536 times 18 quintillion addresses
RIPE delegates a /29
That's 524288 sites with 65536 subnets with 18 quintillion addresses
You can use a /127* on a link, if you want to.
The legacy internet fits in a /96
18 quintillion = 18.446.744.073.709.551.616
* That's 2 addresses 19 / 26

20. Who's who
History
IPv6
Transition
Getting from 4 to 6
There are a lot of transition technologies to get to IPv6
Tunnelbrokers
Dual Stack
DS-Lite
NAT64/DNS64
464XLAT
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21. Who's who
History
IPv6
Transition
Tunnel Brokers
Tunnelbrokers provide a IPv6 enabled tunnel over IPv4 and route several subnets.
Dual Stack
Nodes have 2 IP stacks and several IP addresses
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22. Who's who
History
IPv6
Transition
DS-Lite
ISP Network
IPv6(IPv4)IPv4
IPv6
IPv6 Internet
IPv4 Internet
IPv6
DS-Lite
CGN
Source: Wikipedia
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23. Who's who
History
IPv6
Transition
NAT64/DNS64
The IPv4 internet is mapped to a well-known prefix
64:FF9B::/96
DNS64 translates A records to AAAA records
NAT64 translates requests to 64:FF9B::/96 to IPv4
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24. Who's who
History
IPv6
Transition
"Happy Eyeballs"
Selection mechanism which protocol to prefer (RFC8305)
Tries both address families in parallel, prefers faster TCP answer
"Happy Eyeballs Version 2: Better Connectivity Through Concurrency"
Implemented in
Chrome, Opera, Firefox
macOS
cURL
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25. Who's who
History
IPv6
Transition
Who is using IPv6?
Heise, Google, Youtube, Facebook, Microsoft
NAT64 support is mandatory for Apple iOS Apps
Microsoft is migrating to IPv6 only internally
https://labs.ripe.net/Members/mirjam/ipv6-only-at-microsoft
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26. Who's who
History
IPv6
Transition
Questions
Questions?
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