IPv6 is or isn't backwards compatible with IPv4.

ISN'T.  They pass each other on the wire "like two ships passing in the night". There's not translation, no gateway.  The fact that computers and routers understand both at the same time ("dual stack") is just for the "transition period".

How many bits in an IPv6 address?

128 bits

or

16 bytes

or 

32 hex digits (8 groups of 4 digits)

True or False: With IPv6, NAT is not needed.

True. However you will see it on networks where the network administrator is incompetent.

In IPv6, ARP is replaced by...

NDP (Neighbor Discovery Protocol)

1993: Work began 

1995: First draft complete.

1998: Official specification complete.

1999: First IPv6 addresses allocated.

2012: Declared the default for new IETF standards.

All you really need to know is that design started in 1993, things got real in 1999, and in 2012 things got real real.

In the fictitious IPv6 address: 2222:2222:2222:2222:2222:99:2222:2222 the "99" means "0099" or "9900"?

0099

2222:2222:2222:2222:2222:0099:2222:2222

In the IPv6 address: 2222:2222:2222:2222::1 the "::" means...

...as many zeros to pad the IP address to 128-bits.

lowercase:

a, b, c, d, e, f

(Technically either but there is a movement to adopt a "canonical form" that recommends lowercase)

::ffff:192.0.2.124 is an...

"IPv4 mapped IPv6 address"

Should never be seen on the wire.

May be used to store either kind of address in 1 variable.

(See RFC 4038)

IPv4: http://100.100.100.100/index.html

IPv6: _____

(how is a raw IPv6 address included in a URL?) 

Surrounded by brackets:

http://[2001:db8:ab:cd::3]:8080/index.html

http://[2001:db8:ab:cd::4]/blah.txt 

Subnet size /32

Identifies an ISP (other sizes exist too)

Subnet size /48

Typical organization supernet size.

Subnet size /56

Typical residential supernet size.

Subnet size /64

Typical subnet size.

Subnet size /127

Subnet size /128

Single IP address or Loopback address.

IPv6 DNS records

"AAAA" or "Quad-A".  Like an "A record", just bigger.

IPv4: in-addr.arpa

IPv6: _____

ip6.arpa

Reverse DNS:

IPv4: 4.3.2.1.in-addr.arpa (reverse the IP's octets)

IPv6: ______

Reverse each hex digit:

4.0.e.f.0.0.0.0.0.0.0.0.0.0. 0.0.2.b.7.0.2.0.9.3.8.b.d.0.1.0.0.2.ip6.arpa.

IPv4: broadcast

IPv6: _____

Nothing! There is no broadcast in IPv6.

There's always a multicast channel (address) assigned for anything you would have used broadcast for.

Only communicates on the same subnet.

fe80::/10

That is fe80:: to febf:ffff:... but only expect to see ff80::/64 for now

fe80::/10

Link Local address

Unique Local Address (ULA)

Replacement for RFC 1918

fc00::/7

fc00::/7

Unique Local Address (ULA)

(replacement for RFC 1918)

Unspecified IPv6 address.

An efficient one-to-many form of communication.

MLD (Multicast Listener Discovery) manages it.

ff00::/8

MLD

Multicast Listener Discovery

(manages multicast)

ff00::/8 (any address starting with "ff")

ff02::1

Multicast address: All nodes on the link.

Multicast address: All nodes on the link.

ff02::1

ff02::2

Multicast address: All routers on the link.

Multicast address: All routers on the link.

ff02::2

ff02::5

Multicast address: All OSPF routers on the link.

Multicast address: All OSPF routers on the link.

ff02::5

ff02::6

Multicast address: All OSPF DR (Designated Routers) on the link.

Multicast address: All OSPF DR (Designated Routers) on the link.

ff02::6

ff02::12

Multicast address: All VRRP routers on the link.

Multicast address: All VRRP routers on the link.

ff02::12

ff02::1:2

Multicast address: All DHCP servers and relay agents.

Multicast address: All DHCP servers and relay agents.

ff02::1:2

SLAAC: Stateless Address Autoconfiguration

What used to be ARP & DHCP but no DHCP server needed!

Router feeds node just enough info to get by.

Add DHCPv6 and you get centralized allocation and address assignment too.

IPv4: ARP

IPv6: _____

ND Neighbor Discovery

Uses multicast, uses ICMPv6, but achieves a similar goal.

...:ff:feXX:XXXX

Host assigned IP address as a function of its
Ethernet MAC address (Modified EUI-64)
(SLAAC).

This means someone forgot to enable the Privacy Extensions.

(the 7th bit is always a 1 but you won't notice that.  You will, however, notice the ff:fe)

Privacy Extensions for SLAAC
(Stateless Address Autoconfiguration)

Doesn't start with Modified EUI-64, start with a hash of it.

Changes IP address over time.

Should be default on any modern OS.

DHCPv6 uses which ports?

UDP 546 (client) and 547 (server)

UDP port 546 is?

DHCPv6 client port

UDP port 547 is?

DHCPv6 server port

IPv4 DHCP: DISCOVER/OFFER/REQUEST/ACK

IPv6: _____

SOLICIT / ADVERTISE / REQUEST / REPLY

or

SOLICIT / REPLY (if "rapid commit" requested)

When a node knows its IP address and is
just asking for other parameters:

• DNS (technically "DNS Recursive Nameservers")
• DNS Search List
• NTP servers
• SIP servers
• and many more

2002::/16

6to4 tunneling in use.

2001:0000/32

Teredo tunneling in use.

IPv4: 169.254.173.198 (ad hoc)

IPv6: _____

No direct equivalent.

None needed due to Link Local providing the same feature, just differently.

Firewalling IPv6 is complex because...

1. ICMPv6 can't be blindly blocked. See "RFC 4890: Recommendations for Filtering ICMPv6 Messages in Firewalls."
2. IPv6 "extension headers" complicate how to find TCP/UDP port numbers.

IPv4: ping and traceroute

IPv6 : _____

IPv4: arp -an

IPv6: _____

IPv4: netstat -rn

IPv6: _____

• Mac & *BSD:
• netstat -rn -f inet6
• Linux:
• netstat -rn --protocol=inet6
• Also acceptable: ip -6 route

"Dual Stack"

Running both IPv4 and IPv6 on a host.

We'll do this until IPv4 is completely

eliminated from the planet.

The biggest benefit to starting IPv6 deployment now...

IPv4: gethostbyname()

getaddrinfo()

IPv4: gethostbyaddr() 

IPv6: _____

getnameinfo()

IPv4: inet_ntoa() 

IPv6: _____

inet_ntop()

IPv4: inet_addr() 

IPv6: _____

inet_pton()

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