Airport can't connect to internet

[RLesko]

I'm experiencing some funny problems with my MBP recently (2008 model). My wireless internet works fine at home, but at work it cannot seem to get an ip address (it shows full strength but says can't establish ip). Since it is an office building resetting the modem etc. are obviously out of the question. Any idea what to do?

Also, in my home last night I noticed a warning saying I had the same ip address as another computer in my household. Any idea what could be going on here? (The internet seemed to be working OK during this period).

Thanks.

 

[squeakr]

Did you change your settings and are manually assigning your ip address, instead of having it assigned through DHCP (which could cause your work to deny the connection if the ip address is reserved or already in use). Have you made any changes recently to anything, as this could result in strange issues? Have you tried to restart your computer as well (amazing what a reboot can do, even on a Mac which usually aren't as necessary as on the Windows counterparts).?

 

[RLesko]

Did you change your settings and are manually assigning your ip address, instead of having it assigned through DHCP (which could cause your work to deny the connection if the ip address is reserved or already in use). Have you made any changes recently to anything, as this could result in strange issues? Have you tried to restart your computer as well (amazing what a reboot can do, even on a Mac which usually aren't as necessary as on the Windows counterparts).?

No, I have not touched my IP address at all. All settings are set to automatically configure. And yes I've tried restarting, even upgrading from snow leopard to lion. The issue persists.