A conference named Bob 2.0

The Internet architecture’s end-to-end principle was broken with the introduction of NAT, Network Address Translation. Most client/server applications work properly when the client is behind a NAT, but for peer-to-peer communication there’s no way to find each other if both are hidden beneath NAT, on private addresses.

Addresses you can use for NAT 

The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets:

• 10.0.0.0        -   10.255.255.255  (10/8 prefix)
• 172.16.0.0      -   172.31.255.255  (172.16/12 prefix)
• 192.168.0.0     -   192.168.255.255 (192.168/16 prefix) 

There are several technologies that help realtime applications with NAT traversal.

• STUN - a discovery protocol
• TURN
• ICE

Links about NAT

• RFC 2633: IP Network Address Translator (NAT) Terminology and Considerations
• RFC 4787/BCP 127: Network Address Translation (NAT) Behavioral Requirements for Unicast UDP
• RFC 1918/BCP 5: Address Allocation for Private Internets

 

This page has the following sub pages.

• STUN - Simple NAT discovery
• TURN - Traversal Using Relay NAT
• ICE - Interactive Connectivity Establishment