Problem with Macbook air automatically not acquiring free wifi network dns or router address

Question

I have this problem when my macbook air sometimes does not connect to free wifi hotspots. When the problem happens and I try to run the diagnostics, it normally gets to yellow network settings tab. It seems that it for some reason does not acquire automatically the router or dns address. Sometimes after I shut it down and restart it magically connects to the wifi hotspot but it is very inconsistent. Anyone knows a fix for this problem?

Solution

You may want to try changing the service order. What effect this actually has, I'm not positive, but it's worth a shot:

1. Go to System Preferences and click Network under Internet & Network

2. Click the little options button under the services list and choose "Set Service Order...".

   

3. In the list that pops up drag your wireless service, likely called Airport, to the top.

I've heard some claims that this is caused by TCP packet timestamps not agreeing, but I can't find the link (great). Maybe something related to this.

Comments

[David Yates]

do you see this with any other devices on the same network(s)?

[squircle]

I am having this same problem on my MacBook Pro; seems like it's not model-specific.

[tyblu]

>2k views and no votes? What is this madness?

[harrymc]

@thepurplepixel: Not responding to the suggested answers means wasting your bounty rep-points for nothing.

[squircle]

@harry I kinda hastily posted this bounty and forgot about it; I'll do that now. Thanks!

[Rumsfeld]

yes, it does - it's come to a point that I have set up locations with manual settings for home and other networks I use on regular basis just to avoid the frustration. I guess I mentioned "free wifi" just to emphasize that it is not a login or access problem.

[squircle]

Flow control only applies to wired ethernet, which I have no problem connecting through. The only change-able option in the advanced settings for a wireless adapter is the MTU, which is set at the standard 1500. Also, I have IPv6 off by default and the problem persists. When I look at Wireshark, I just see a bunch of DHCP Discoveries being put out, as well as some broadcast (255.255.255.255) traffic from the network (not broadcast like 192.168.0.255/24).

[squircle]

Service order is basically what connection to prefer when there are multiple connections available, which is not the case for me. Also, I don't know if it has to do with the timestamps not agreeing, because when I look at Wireshark, there aren't any ACKs from any TCP packets on my computer. Oddly enough, I think this may be a DHCP issue, as when I set a static IP, I can connect fine, but only for 10-15 minutes.

[squircle]

I've done all of the preference resets and permissions checks, but the issue still persists. I hope it isn't hardware-related.

[tyblu]

@thepurplepixel, I have the same problem, though lately it doesn't seem to be surfacing. Maybe one of the recent updates fixed it for me. Maybe the neighbors turned down their MegaMechaMicrowave furnace. The way I avoided the problem was listening to a radio stream on iTunes and turning the volume all the way down. The constant stream seems to keep the internet demons (daemons? ;) at bay.

[tyblu]

@thepurplepixel, Also, I know what the primary purpose of Service Order is, but there appear to be secondary effects in changing it. For example, my improved wireless connectivity. ;)

[squircle]

I cannot fathom why, but this seems to have fixed the problem for me. Thank you so much for your suggestion!

[ridogi]

Can you connect if you are logged in as another user? How about if you have a clean OS on an external drive booted via Target Disk Mode. support.apple.com/kb/ht1661 That will eliminate the possibility of software problems in your user and in your OS install. If you have the same problem with these two then it is a hardware problem.