Private ip address
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Revision as of 19:36, 28 June 2012
When private internet IPv4 addresses are used on the LAN (often).
The allowed private addresses are specified in rfc1918:
- 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)
Note: Private ip addresses must be (source) translated (NATted, tcp, udp: PAT) to a public (=non-private) ip address (tcp: socket) before its payload can be send into the (public) internet.
NAPT (network address and port translation) is a necessary because of to few public internet IPv4 addresses. NAPT is commonly referred to as NAT (Network address translation).
The NAPT is normally done by a router or firewall with NAPT functionalty.