deja.com, zoeken op 'apple release DHCP'..
antwoord:
OT DHCP changes from release to release, so I'm going to specifically speak to OS 8.6...
No, there isn't a specific option to release a lease immediately. At least, not by Apple. There are (non-obvious) ways to do it, though.
First, there's the TCP/IP Options control panel (posted by Apple, on the 8.6 cd-rom), that allows you to check 'don't retain lease something-or-another' that will tells OT to always issue a DHCP RELEASE when the stack is unloaded. You'll really want to check Apple's TIL (til.info.apple.com) for more details on this if you want to do this. You have to be careful with this option because some services only support a subset of possible DHCP behavior and therefore may not work properly with
'don't retain lease' checked. Second, if the Mac is offered a lease on an IP address that is already stolen at the time of the offer, the Mac will ARP the address and find out
that it is already in use. It will then issue a DHCP DECLINE to the DHCP server, as it is already taken. Also, some DHCP servers will PING an address before it offers it to protect against this.
Third, if someone steals your address after you've received a lease, you can turn off TCP/IP and turn it back on. When you do this, it unloads the stack and then reloads it. If you have the 'don't retain lease' setting enabled, then it'll require a brand new lease that won't be stolen because of my second point. If you don't have the 'don't retain lease' setting enabled, it'll request the old lease back...I haven't checked to see if it re-ARPs to check against address in use as in my second point, but I expect it does.