Upgraded to OS X lion and now I cannot connect to the Internet. Wifi or hard wired. Any ideas?

Ok, for some reason I wanted to reboot again. With the Mac built in firewall "on" i'm not able to connect again. I turned it off and rebooted and now am able to connect again. I did complete shutdowns 3 more times and am still able to connect. Basicaly turn the firewall off and leave it off until Apple patches it.

Try this:

Backup this file in /Library/Preferences and the delete it.

Command 1:

sudo mv /Library/Preferences/com.apple.alf.plist /Library/Preferences/com.apple.alf.plist.orig

Command 2

sudo rm /Library/Preferences/com.apple.alf.plist

Now reboot your machine and then turn the firewall ON after a reboot. Then reboot a couple times and test if everything works.

File doesn't exist to move. I did a PRAM reset some hours ago. That could be why.

ok, airport says i am connected and chrome seems to work fine, also mail, but the app store, twitter, facebox and stuff ike that just wont connect, anyone knows what is happenning?

What have you done so far? From what I read removing AVAST seems to fix most poeple. For me, it was disabling the built in Mac firewall.

well i dont have avast or any other antivirus. i tried disabling the built in firewall and nothing.

i dont really have a problem with chrome or safari, anything else just wont work, i tried searching for upgrades and i couldnt connect either. i have read a bit about dns and dhcp but everything seems to work just fine. I dont have a clue on what is going on at this point. when i try the assistant it says that there was a change and askes for my wep again, and the same message keeps appearing, anyone with this same problem?

The only thing that I could suggest might be a DNS cache flush.

dscacheutil -flushcache

well i flushed every system cache and it seems to be working now, dont really know what happened, mabe the apps didnt accpet the change from snow leo's airport to the new one or something. Thaks a lot, hope i wont be aving problems again.

No problem. Good luck.

the problem seems to be the built-in firewall, cause as soon as i turn it on it stops working again. am i supposed to leave it off? is someone else having this problem?

I left mine off. When I enable it again I get DHCP issues and DNS issues.

ok i just saw u have the same problem and that im supposed to leave it off, sorry for the trouble, wasnt paying attention. lol

It's all good. I'm just glad what I found was able to help someone else.

octamm, try this:

Backup this file in /Library/Preferences and the delete it.

Command 1:

sudo mv /Library/Preferences/com.apple.alf.plist /Library/Preferences/com.apple.alf.plist.orig

Command 2

sudo rm /Library/Preferences/com.apple.alf.plist

Now reboot your machine and then turn the firewall ON after a reboot. Then reboot a couple times and test if everything works.

ALso if you guys click Advanced in Firewall, do you guys have 'Block all incoming connections" or "enable Stealth mode" checked ?

Make sure your applications have access too and are set to "Allow incoming connections". Then re-enable the firewall and test.