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Username: pchitescu
Date/Time: Mon, November 20, 2000 at 4:08 PM GMT (Mon, November 20, 2000 at 7:08 PM EEST)
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Score: 5
Subject: IP transfer should be avoided


ISPs generally decline transfers of IP addresses especially when class C addresses are involved.

Transferring a block of IP address classes should be avoided as it loads the IP routing tablesif fragmentation occurs. Whenever possible IP addresses are keept in aggregates that need less  space in the routing tables. For example, 16 class C blocks that have 4 common bits in the network part can be exported (by the routing protocols) as a single entry as long as they 'belong' to the same ISP as far as the rest of the world is concerned. All packets will be routed to the same router(s).

If all address blocks were exported stand-alone then routers will have to keep millions of entries (for class C addresses) in their routing tables. This is unacceptable.

If these addresses were not exported aggregated with other addresses then it would be no technical reason to not transfer IP addresses. However, that will happen only to class A and B addresses.

BTW, assuming a fixed IP address is a bad networking practice. That's why protocols like RARP/BOOTP/DHCP and DNS/WINS/LDAP were developed, to allow hosts to pick up an IP address and to make human accessible names invariant to IP address change.

Paul Chitescu  |    |

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