MacBook – mid-2011 MBA: sluggish wifi on WPA/WPA2 networks

airportdnsmacbook proNetworkwifi

Machine specs: Mid-2011 MacBook Air with a 1.8 GHz Intel Core i7 processor, and 4 GB DDR ram, Intel HD Graphics 3000 384 MB, OS 10.9.2 (Mavericks).

Wifi connection is sluggish with multiple ISPs on various WPA/WPA2 networks (home, friend, family, etc.) but works fine on large public networks (e.g. Starbucks) as well as the university network where I am a student. My other apple devices (iPhone and iPad mini) work fine on the same WPA networks which are giving my 2011 MBA trouble.

After and in-depth search of this site and a few others, I’ve tried the following trouble-shooting steps to no avail:

Hardware inspection of airport card by Apple technician revealed no damage
Fresh “erase and install” of the OS 10.9.2 (did not use time machine backup out of fear of cloning the problem back onto my machine)
verified and repaired permissions and disk from Disk Utility
verified and repaired Keychain
verified that the wifi was also sluggish in safe mode and restore mode
hard reset of WIFI by erasing the appropriate system preferences plists
created a “test” location in Apple network preferences; erased and created Wi-Fi in network preferences
flashed the PRAM/ NVRAM
changed DNS servers manually
checked the activity monitor and ran Sophos Anti-Virus to check for malware, viruses, etc.
turning off the bluetooth
dragging the appropriate network to the top of the list
renewed the DHCP lease from network preferences
reset the MTU manually to 1453 (default is 1500)
flushed the DNS cache in Terminal (dscacheutil -flushcache)
turned the Apple security firewall on and off again

At this point I'm thinking it actually may be a hardware problem that was overlooked by the Applecare technician. Would it be worth buying a new airport card and installing it myself?

Thanks, all, for the help!

Best Answer

Turns out one of the internal antennae in the monitor was not properly connected to the airport card. After properly securing the antennae the wifi problem was fixed immediately. Evidently the problem affected the signal strength and reliability, even though it showed full bars on the menu bar.

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MacOS – Local DNS circumvented when WiFi is active

I think the DNS settings for each device are independent, so you need to configure DNS in the Advanced tab of system preferences for each NIC (en0, en1, etc.)

MacBook – 2011 MacBook (10.6.8) connects to AirPort but intermittently won’t connect to webpages

The main thing that looks odd from the setup that you've mentioned above is the DNS server. It appears that the IP address your computer has allocated is being assigned as the DNS server? If you're not running DNS services on your computer, this won't work very well.

Try to remove the single DNS server (i.e., your computer's IP address) from the list of DNS servers, and see if the machine populates that list with other entries (that were potentially provided via DHCP). If there are no DNS servers listed in that dialog box after you remove the single entry, I'd suspect configuration problems on your network.

Alternately, it may help to manually configure that network interface to use Google's open DNS servers (8.8.8.8, 8.8.4.4) to see if they will respond correctly to DNS lookups.

You can use the Network Utility program at /Applications/Utilities to perform further network troubleshooting. For example, it should be possible to "ping" the DNS server, router (gateway) and some outside host from where you are. This lets you know that your machine can communicate with those devices. First, I'd recommend trying to use Network Utility to ping the DNS servers that are being provided via DHCP. Under the "Ping" tab, you can enter the IP address of each of those hosts, and click "Ping" to see if you get a response. If all of the DNS servers are responding to pings, see if you can ping the gateway (10.58.204.1). If you receive responses for pings to all of the 'internal' hosts, see if you can ping some outside host (gmail.com?) to see if your computer's network traffic is being routed to the Internet.

If all of the ping tests are passing, I'd recommend trying to perform DNS lookups on the servers that are showing up in the DNS table in Network System Preferences. You can use the Network Utility program to perform lookups, but it may be more helpful to diagnose the DNS servers individually using 'nslookup' through the Terminal program. Open Terminal from /Applications/Utilities. When the program opens, you'll see a command prompt. Type in the following queries, and observe whether or not you receive valid responses from all of the DNS servers provided:

nslookup gmail.com 172.16.2.5
nslookup gmail.com 172.18.82.11
nslookup gmail.com 4.2.2.2

Those servers should respond with some answer (and IP address for gmail.com) within milliseconds. If you're seeing the commands hang for excessively long periods, that particular DNS server may not be responding correctly.

It's odd that you're having intermittent issues when using Google's DNS servers...If you're on some larger private network (as it appears you are based on the private addresses being provided), it's possible that traffic is being filtered.

Lastly, the Awarenet profile that you're using is simply utilized for authentication to a wireless access point named "Awarenet" that uses 802.1x (WPA Enterprise) security to authenticate users (you're signing in as egoodwin). If you no longer use/join a Wi-Fi network named "Awarenet" (for work, or school?), the profile can likely be deleted.

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