MacBook Air connected to internet, but no connection. Help!

[ltn318]

I have a Macbook Air that's about 4 months old, and it's giving me problems connecting to the internet. It goes like this...

About two thirds of the time, I select the network I want to connect to, put in the password, it works and I can connect to the internet. No problems.

One third of the time, I find the network I want to connect to, put in the password, the password is accepted, the internet icon on my top bar fills in indicating a strong signal, but I can't actually connect to the internet. Any website I go to says that it can't connect because I'm not online. But I'm connected! The password worked! The bars are lit up! Soon after this happens, the (!) icon appears in the top bar on my screen, and it says 'no internet is available'.

A quick Google search has indicated that a number of people with Macbook Airs have this problem, but I haven't been able to find a good solution. The networks, routers, etc. I'm using are not mine (I'm currently traveling), so I don't have the ability to change their settings. This happens seemingly at random, in various places in each place I visit... there doesn't seem to be any rhyme or reason to it.

Thanks in advance for your help and suggestions!!

 

[Beaverman3001]

Those particular networks could have a DNS outage, or no actual internet access to begin with. Just because you are on a network, does not mean you are connected to the internet. Your problem is very vague and broad, and considering it isn't on your own network, we can't exactly help you troubleshoot it.

 

[ltn318]

airport shows connected. im using a pc that works on the same connection.

right now i am connected through the ip address, dns and router codes. and i am using a pc thats connected to the wireless i want to use and its working just fine. the router is tcom speedtouch and it does look a little old but there is no other identifying info on the router itself. please let me know if there are any other questions that might be helpful in figuring out why the mac cannnot connect.

MBA cannot connect even though PC can

And by connected i mean it shows green on the airport signal but the wireless just says contacting apple or google for about five minutes and then times out. the wireless does not actually work. also how do i know if there is a dns outage and if that were the issue would it work on a pc