Q: Installed Lion, now cannot connect to internet!!!

Hootie, my advice would be to not upgrade. One thing you might try is testing on a separate partition.

My review of Lion is thus: the only really exciting feature is Versions, but this will not be up and running until developers have worked it into their software.

Other changes are small and mostly cosmetic.

I had that problem right after I upgraded to Lion, my wireless said I was fully connected but the internet wasn't working.  I plugged my computer in with an ethernet cord and all was well.  I ended up checking network connections and deleting some un-used wireless networks, re-arranged the order of preference, and about 5 min later it all just started working....hope this helps!

Strange thing for me is that not only is my Macbook losing its wireless connection but every computer connected to my Linksys router is also losing it. I have to reset the router to get it working again. That doesnt last though because it eventually dies again. I have to disconnect my Mac from the network to keep it up for the other computers. Somehow Lion is killing my router.

This worked for me. I just selected my new location that I created and now it connects to my wifi network that is running on my TimeCapsule.

Thanks!

New to IMAC, but have found that if I reboot each morning I can connect to wifi just fine.  If I do as asked and go through process of re-entering my WEP, no luck.  Without a re-boot, no wifi connection. 

Why should I have to reboot? For years I've just closed the lid and let my laptop sleep. I never reboot. One of the beautiful things about Macs is waking them up and getting to work without rebooting. This does not make sense. I expect that whatever this issue is it will be resolved soon.

I have same connection problem like yours. It is really annoying. I did everything that I read forums but nothing helps. I hope it solves soon,

Thanks to HootieUK for his tip

I was able to fix the problem finally!!!

I found out that previous "kernel" extensions from previous old programs were not compatible.   I looked up instructions for cleaning up my kernel extensions as well as any turning off other non-Apple daemons that start up.

The web site is:   http://www.hackerskitchen.com/mac-old/startup-items-detail.html

My recomendation is clean up your kernerl extensions and daemons.  after your Lion is restored, then look at how you can re-install the affected applications or find a replacement for them.

MY RECOMMENDATION:

Load Lion on a Mac you don't use often and only to try out the system.  OR, if you have a recently "INITIALIZED" Mac with just Snow Leapord and nothing else installed.

I'm seeing bizarrely very high latency, jitter and packetloss between previously rock-solid hosts on the same Airport network since upgrading. Strangely the same is not true of their connectivity to the local gateway.

Haven't fired up Wireshark yet but it's most unusual. Will be looking for arp & wireless misbehaviours.

This has got to be something more devious than a firewall issue. I tested three sites using my new Macbook Air running Lion and my 5 year-old Mac PPC portable running Panther.

Site 1 - Draytek router. BT. Both machines fine.

Site 2 - Dlink router. AOL. Both machines fine.

Site 3 - Sagem router. SKY. PPC fine. Air brings up an exclamation mark on the wireless symbol. Sometimes connects and then falls off.

The Air was fine at all sites under Snow Leopard last week.

While all sites use WPA encryption when you really got into the internals of the settings I found that the Air was rejecting the password on site 3 at times even though it was fine on the PPC.

So something to do with encryption perhaps? TKIP or AES decryption issue?

I have the same problem Internet works for about 10 min then disconnects.  Cannot connect back unless I do a full restart help apple...

ok im on a complexed network with windows server 2008 yes its windows but ok this is tagging along with similar mac issues i am using my mac via WIFI IF I USE WITH NORMAL JUST WIFI NOTHING WORKS STORE MAC UPDATER AND SAFARI THAT IM CURRENTLY USING ATM OVER WIFI

i had to use wired after thinking about it for a month looked at the settings again today

low and behold  I had to use a vpn into my server yes a VPN connection that i never had to do and im thinking what the h to the f  never needed to use vpn only when im out side my network and  and to spannerdarl i have the auto proxy discovery enabled didnt do anythingim slightly happy but not fully

so a summary

using macbook

wifi on and using the 5 g net and yes tried the 2.4 g  nothing worked safari mac updater and i believe also msn oh and skype works yes this is odd

to get it all working used my own VPN  everything came back to life all programs worked mac updater mac app store  everything including msn

they messed up a setting some where / codeing is missing or wrong

ok i posted same thing else where but seems relevent here too

some steps you may like here

Message was edited by: reginaldfrombillingshurstuk added a bit about wired

for here i am sort of double posting on this forum

posted under

ok i did a step you may have the auto pproxy discovery enabled in wifi

click wifi and go advanced then go to the proxies page and uncheck the auto proxy descovery  i guess this is the resolution

like it if it works for you

i also did another step turn off my time capsual i bet this did absoluly nothing  but give this a go

the tech  guy on phone told me today

Same issue with me, Connect fine, than randomly the my MBP disconnects, airport pops up with the exclamation mark. Says there is a problem with network settings yet my macbook still on snow leopard and iPhone running fine. Becoming a nightmare. Trying to print a large document, cant get past page 5 before I lose network connection! Using an airport extreme, surely there is some sort of update coming soon?

Thank you to everybody who has posted in this forum. Unfortunately, nothing suggested has worked for me. Ethernet works, wifi will not work at all. I don't have the firewall on, no anti-virus software, I removed Little Snitch, and I don't have Avast. No matter what I do the wifi ip still shows the dreaded 169.254 address. I hope Apple fixes this soon.