View Full Version : 10.5.7 failing to acquire DHCP address - any ideas?

Jun 28, 2009, 02:24 AM
A friend is trying to connect his MBP 17 (2.6GHz) to our office wifi network, but it simply isn't working. Despite entering the correct username and password, he gets constant "8021.X authentication failure" messages, and/or the machine fails to grab an IP address via DHCP and generates a self-assigned IP address so he has no internet connectivity.

Nobody else in the office running Mac laptops has any problem, and my friend can connect to the network using his iPhone with no issues at all. The only way his MBP will connect is via an Ethernet cable, and that's not a practical option going forward. Needless to say, he has no issues connecting his MBP to *other* wireless networks.

So - any suggestions? We've been round and round on this and have reached the point where we think a reinstall of OS X might be necessary. Our IT department has no clue either, but then they don't really understand Macs anyway.

Jun 28, 2009, 07:20 AM
which variant ?

Jun 28, 2009, 07:37 AM

Jun 28, 2009, 07:40 AM
Are you sure the wireless access point isn't doing MAC address filtering?

Jun 28, 2009, 08:12 AM
Absolutely certain that there's no MAC filtering going on. As I say, my friend can connect using his iPhone with no problem at all, but it just won't work for his MBP. There are many other people in the office with MBs and MBPs (including myself) and we've never had a problem either.

I think next step will be a reformat and reinstall of OSX.

Jun 28, 2009, 10:21 AM
Our IT department has no clue either, but then they don't really understand Macs anyway.

They don't need to understand Macs - it would be sufficient if they understood the network technology that they are using, because it's standardized. They should be able to tell you what authentication and encryption methods they are using and how their network is set up.

OS X supports a couple of wireless encryption/authentication protocols, including what they call "WPA Personal", "WPA Enterprise", "WPA2 Personal" and "WPA2 Enterprise". The difference between WPA and WPA2 is the used encryption algorithm.

I don't know your network, but "WPA Personal" works in most everyday cases and you should try this one first.

It should also help if you just use the very same configuration that the mentioned iPhone uses. After all, both machines run OS X...

Jun 28, 2009, 10:24 AM
Bit of a long shot:

As it's an office environment, are you SURE your friend is trying to connect to YOUR office network, and not the one next door? Is the SSID he is seeing correct (i.e. belongs to YOUR office) - assuming the SSID is visible at all, of course!

Jun 28, 2009, 06:44 PM

WPA is a username and password combination, 802.1x isn't. perhaps as another poster has suggested, he is connecting to a different network, or if your network is setup with 802.1x, you need to get the assistance of the person who set up 802.1x for you.

Jun 29, 2009, 01:05 AM
He's not connecting to the wrong network (the SSID is visible) and the people who set up 802.1x can't work out what the problem is. It's one of those incredibly frustrating situations where there's no obvious reason why it shouldn't work, but it won't - and that's even more infuriating with OS X given that normally, it just works...

Jun 30, 2009, 05:16 AM
Reinstalling OS X fixed the problem. Must have been a corrupted file somewhere. He had dozens of previously-used wireless networks saved, so maybe that had some bearing on it too.