How To Fix Self-Assigned IP Addresses In Mac OS X [Video How-To]

CHoa

It's not solving the problem, the IP address on Airport and Ethernet
before and after the demo starts with 169.xxx.xxx.xxx which means there
is no internet connection...

Euge Barannikov

5 minutes of my wasted time listening to your bullshit.

Raynold Von Samson

THANKS! This worked for me!

EnglishChris

Thanks for the advice - I tried this at first and didn't work. I just tried deleting all of the 'System Configuration' files along with the 'com.apple.alf.plist' file from Preferences and after I created a new location in the 'Network' control panel it's all up and running again.
Thanks everyone who contributed - including the guys who pointed out you can get to the System Preferences/Network control panel from your Apple menu! ; )

EnglishChris

This doesn't work!Follow this: Go to Macintosh HD-Library-Preferences-System Configuration. Delete all of the files along with the 'com.apple.alf.plist' file from Preferences and restart. Go to System Preferences (in the Apple menu or even in the main Apple dock!) in the 'Network' control panel go to Location, scroll down to 'Edit location' add a new location. Then click 'Apply' - it should dial up a new location with a nice new fresh connection.
See DM Cook's response below - it's more likely to be due to a corrupted Preference file - things like this often are!

Tatiana

The reason why very few of you are getting this to work is that you're all looking at the Mac as the source of this problem. This is not always the case, ESPECIALLY if your Mac gets online just fine everywhere else.

The way any wireless device (computer, cell phone, pda, whatever) gets online with a wireless router works is this: When your computer connects to your home/work/whatever wireless network, there's a handshake that occurs. The router says "I see you, [device with mac address __________], and I see that you have my WEP/WPA password (if necessary). I grant you access to my network. Now you need an IP address to actually get online. Here's IP address 192.________. Enjoy!"

The problem you're having with a self-assigned IP is that the router lets your computer get on the wireless network, but then fails to give it an IP address for whatever reason. In Mac OS, your computer will attempt to give ITSELF an IP address. Hence the term SELF-ASSIGNED IP. This is always a 169.______ IP. It obviously doesn't work, because 169.________ is not in your router's valid IP range.

The quickest way to resolve this (without trashing your entire system network configuration once a week) is to power cycle your router. This is achieved on most basic routers by simply unplugging the power from the BACK OF THE ROUTER for 60-90 seconds and plugging it back in. Wait til your router's lights go back to normal and connect. This should force your router to get its act together and dole out IP addresses like it was meant to do. It works 95% of the time. Some routers, specifically router/modem combinations (if you only have one box to connect to the internet, you have a combination) have special instructions for power cycling. Sometimes unplugging for that long can actually completely reset them. Consult your manual or your ISP/router manufacturer for those special instructions.

To prevent this from constantly happening:

Depends. Some router manufacturers STILL don't write firmware for their routers that play nicer with Macs. It's why most of the time when this happens, you'll see that the old Dell in the den connects just fine, but your brand new Macbook Pro can't get online to save your life. D-Link routers tend not to play nice with macs, particularly the models provided by the ISP. That cheap-ass Netgear router/modem combination box Comcast has given everybody and their mama can have this problem too. It DEFINITELY doesn't play nice with Android phones, if you have one. If nothing I've proposed in this post works for you, get rid of your router, especially if your cable company gave it to you. It's the cheapest router they can provide while still charging you $60 a year for it with no replacement plan, lol.

Make sure your router has the latest firmware installed.

Also, make sure your router has enough IP addresses to go around. Not too long ago, most households only had 1-2 wireless devices and so owners would set their routers up with an IP range of about 5 addresses and call it a day. Nowadays, you've got your notebook, the PC downstairs, your kid's computers, their iPads/iPod touches/PSPs/Gameboys all on the network. Sometimes all of them are hogging up an IP addresses at once, in which case your router just runs out of IP addresses to give the last device to try and get online. Check your router's preferences and make sure you have a wide enough IP range. You may also see messages along the lines that another device on your network is using your IP address. This is usually the culprit.

If your router is just ancient and hails from a time before everyone had a Mac, replace it with something newer. Linksys routers have been playing nice with Macs since the good old WRT54G.

Kayne Ottley

your a legend works a treat

Brad Chase

HERE IS THE FIX!!!! - If none of this works for you (which it didn't for me), reset your router to factory settings by holding down the little reset button. Then setup your network again. This worked for me. 

vovtz

Sorry DM, your instructions didn't work for me. I removed all 3 files and rebooted. After that the Network panel in System Preferences still remembered most if not all previous configurations. I'm using OS X 10.6.8.

Tonight I will try to connect by wire to my router at home.

[Conclusion: it worked with the router at home, so my problem was not with OS X, but with the DHCP server at work; has now been resolved.]

Yevgen

Hi,
Thank you very much!
It fixed my problem!

lemons69

Many thanks for this .... Got me out of a very sticky spot !

welcomeahmed's page!

http://reviews.cnet.com/8601-1...

Miriam Hamsa

Worked for me. I had to mess around with a few more network settings, but I'm up and running for the first time in a week. fingers crossed that it stays up. I spent hours on the phone with ATT, replaced my router, had an ATT tech come to my house.... nothing worked. Everything I read said to reinstall your system, which I didn't want to do. The people at the Apple Store, where I had an appt for this afternoon, refused to tell me if they would do the clean reinstall for me, and honestly, I didn't want to go down there in the rain. So, I made one last search online and found your video. Will it continue to work? I don't know. But this is only the second time this week I've gotten a good solid connection, and the first one only lasted ten minutes.

Shant Shahrigian

I don't seem to have the file called com.apple.alf.plist on my Max OS 10.4.11.

Any equivalent I could try to delete??

Many thanks.

akexcerio

Im in a hotel- with a wireless network that uses a web browser log in.however i cannot get even that far.i have a self assigned IP - 169.254.205.223 this happens a bit but ive always been ablero dhcp lease my way out of it.or resort to a cable. But not here.confused as fuck.ive removed the com.apple.alf.plist but its made no difference.and the wireless betwork isnt in my networks. Im using automatic locations like always.

Confused.lost.annoyed. Can anyone help?

Alexandre Spengler

Hi there,



I spent about four days trying to solve this puzzle. What worked for me
was to change the modem/router password system from WEP to WPA. You can
do that by typing the modem address in your browser and selecting a new
password system. You can still use the same password if you wish.



What happened is that my Imac 27 (10.6.8) wasn't recognising the modem
security setting and therefore the DHCP could not properly assign a
valid IP (..a friend actually explained me that..). To know if that is
really your case, click in the airport icon on the top right of your
screen (the radar like icon) with the "Option" button pressed. Right
bellow the network you are trying to connect it will appear some further
settings like "PHY Mode", "BSSID", "Channel" and finally "Security".

In my case, even though there was a required password to log in the
network, "security" was being shown as "none". So I got in the modem
through a flatmate computer and changed the password system from WEP to
WPA2. As simple as that.



Hope it helps.



Cheers

Shaa'iBe Original

Whaat ?! You didn't fix anything. After your so called " Fix " your ethernet still had an self assigned ip address -______-