On: Rapid DHCP: Or, how do Macs get on the network so fast?

[pacala]

The small print in paragraph 2 explicitly allows reusing the previous address until the lease expires.

[hristov → pacala]

Paragraph 2 only allows this "If a client ... is unable to contact a local DHCP server." Note that in the present example, the client started using its old address before even trying to contact the DHCP server and eventually was able to contact the DHCP server.

[wnoise → hristov]

This could alternately be described as "a client used its old address until it could contact the DHCP server".