Can't get a DHCP address from OS X - but works fine from Windows

You could try DHCP with Manual Address and just choose a number that won't be given to your other machines by accident. Not a perfect answer as your DHCP should work better than it is, but if it works it may help get you online.

These are sometimes stubborn little beasts. I have one that sometimes gets stuck on an IP number and refuses to give it up even when it is allocated to another Mac.

I am afraid I have zero experience of the Boot Camp setup and if (or why) that would interfere with the process.

Have you tried in Network preferences TCP/IP the Renew lease button: I find that sometimes makes it react; as well as restarting the router. An alternative to that is to switch to a manual setting, then switch back to DHCP after pressing Apply (then Apply again). That is like Dechamp's suggestion, but I would add to that and get you to switch back to DHCP. If the manual settings do not work, there may be other problems.

It is not clear how familiar you are with OS X, so excuse me if I suggest basics that you have already gone through: have you tried a different user account, and/or a different location instead of the default Automatic. Airport on/off; cables OK?

There should be (at least) a greyed out DNS number in the DNS settings panel: I presume that is being allocated?


I just remembered that some people had acknowledgement problems and I copied this idea from MacFixit a few weeks ago:

"A lot of people have been suffering slow LAN transfers after the 10.5.2 update and my podcast last week was excruciatingly slow although with local systems, who knows? MacFixit had this item covered last week and suggest that the transfer acknowledgement part of the protocol is to blame as it was too long. It was set to 3 and their fix sets it to 0. A protocol is the sort of handshake that goes on between devices.

The fix is a line of text that is typed into Terminal used in an Admin account:

sudo sysctl -w net.inet.tcp.delayed_ack=0"

As there is NO acknowledgement, I wonder if a change here might help.

Message was edited by: Graham K. Rogers

Just to be pedantic, after the DHCPOFFER you should be seeing a DHCPREQUEST back from the Mac requesting the offered address followed by a DHCPACK from your DNS server.

Out of curiosity, have you tried bouncing your DNS server?