Speaker Glen Turner
Time 2009-01-20 10:40
Conference LCA2009

Running out of IPv4 addresses. We are not moving to IPv6 fast enough.

Plan B. Use NAT:

  • record addresses and ports in table and rewrite
  • no more end-to-end addresses
  • breaks SIPs, webservers, etc
  • NAT - Deep Packet Inspection - Costly inspection.
  • sometimes need to rewrite addresses in protocols themselves.
  • need specialised NAT support for each protocol.
  • Jitter and complexity attacks.
  • Huge amounts of state kept. Ideal target for hackers.
  • soft state, can be refreshed. This is hard state, must be kept in sync on different paths. Protocols to do this are open to exploit.
  • Tables grow and size can get too large for resources. Need timeouts.
  • TCP is a latency sensitive protocol. IPv6 will reduce delays as opposed to using NAT.
  • Without NAT protocols for all protocols, this enables carriers to lock customers into their protocols and services.

Market for IPv4 addresses.

  • Adress holders are sellers.
  • ISPs and colo providers are purchasers.
  • Poor record keeping.
  • Routing tales size will explode as every last IPv4 address used. Some routers will need to be upgraded if static RAM overfills.

NAT is not a good option.

No one is going to make any money from IPv6. Insignificant feature. Belief that it is has dampened uptake. Need to use advanced router to support IPv6. If ISPs don’t provide IPv6 they won’t be as attractive.

Most of what works with IPv4 works with IPv6.

  • Applications shouldn’t be hardcoding IPv4 addresses.
  • IPSEC and QoS backported to IPv4 from IPv6.
  • IPv6 is completely seperate protocol and requires its own routing tables, firewalls, etc.

Three parts of each network:

  1. Network
  2. Subnet
  3. Hosts

Site = 2001:388:a001::/48 Subnet = …:1:217::/64 IPv4 address = ::ffff:

Larger addresses allow autoconfiguration.

We need to cater for when we run out of 48 bit mac addresses.

Ask router for prefix of IPv6 addresses. Router sends advertisements. /etc/radvd.conf.

IPv4 framentation removed. Blocking ICMP6 packets is a really poor idea.

New DNS record type. Reverse DNS looks awful. Dynamic DNS might come to its own age.

Give servers own address that isn’t specific to mac address, so address doesn’t change if Ethernet adapter changes.

Clients ask for AAAA before A.

Hardcoding IPv4 addresses in web pages is bad. Special hell for these people.

Don’t try to change bit allocations for addresses, it may not work.

Do not use EUI-64 on routers. These need to be hardcoded. Use ::1 for router address, no host will have this address.

  • Use stateless IPv6 DHCP server. Does not need to record any information.
  • Use dynamic DNS.
  • Find a happy user somewhere and make them unhappy.
  • Issues: Squid (need latest version), Microsoft Exchange.
  • Issues: netflow format changes.
  • Issues: VPN stuff changes.

Biggest reasons for lack of deployment are management issues. A lot of these are fear of change. Not use to running multiple protocols. Seems scarry.

Australian government believes there are too many unknown security problems with IPv6.

Use tunnel broker. e.g. broker.aarnet.edu.au.

ipv4 != ipv6:::fff:1.2.3

Major problem is the colons in the addresses.

Security: Biggest problem is it is another protocol. Cisco would automatically enable IPv6 if enabled upstream and allow all traffic by default. Problem now fixed.

It is possible for somebody to advertise on IPv6 but not respond on IPv6. Need to have nagios checks for both IPv4 and IPv6 addreesses.

Firewalls, biggest issue.

Training issue. One university shows students IPv6 addresses. Big vendors don’t.

In 5 years time it won’t be possible to obtain IPv4 addresses for affordable prices. ISPs will require people to use NAT. Expect NAT to run about 15 years.

Our IPv6 broker has 6000 users. Being upgraded, as it can’t cope with load. Should last 7 years. Upgrade bill was 6 digits.