Can not access web wifi simble on but can not connect the the internet

Question

wifi on but can not access internet

Answer 1

I COULD SOLVE THE PROBLEM!!!  :    CHANGE YOUR ISP
I it is obvious that we are talking about different issues, but all arise from the same origin. I am a surgeon and fortunately one of my patients is executive manager of one of biggest ISP companies from which I have bought my Internet service for home and my clinic.
One day I told him the problem and he promised to check it for me. A few days later he called me and discussed the exact problem (unfortunately as I am not I.T professional, I couldn’t understand it well, I can just remember he was talking about MULTIPLEXING incompatibility between Mac security settings and that specific ISP multiplexing settings, He also said they had similar problems with some Linux users. I can remember he relate the problem to cheap ISP hardware, which leads to security issues which  are ignored by Windows Systems but leading to connection blockade in Mac Browsers. That’s why if you PING yahoo.com, you will see everything is OK but your browsers are not working)
In fact this is a hardware issue which is related to ISP (Internet Service Provider) security and not your Mac.
The day after, I took my MacBook to some ISP offices and asked them to let me connect to their line just for a test. “ Surprisingly I found out without changing my MacBook’s settings it works well with some ISPs and not with others!! “
I have two ADSL lines: one at home and one in my clinic. First I changed my home ISP and everything is well at home from the day I did the change. But before changing my clinic’s ISP it worked at home and not at the clinic. Later I changed my clinic’s ISP and afterward never I had any problem.  This proves ( as that manager said also) this problem is related to ISP and not Mac itself and that’s why Apple could not have resolved the problem yet: different ISPs have different issues.
Here I can make some suggestions:
1- First, take your MacBook into different ISP offices and find the one which works well (before making the contract and paying money to the ISP, restart the Mac or send it into sleep mode repeatedly to make sure the connection never drops with restart or sleeps)
2- Change your modem:  Modems as TP-LINK, D-LINK, are not well compatible with Mac.  Apple modems or Linksys are perhaps the best choices (this is not main cause of internet drop, but can affect the performance)
3- Make sure your neighbor’s Wi-Fi is not exactly on the same channel as you are using (I use iStumbler for finding my neighbor’s channels)
4- Find best DNS: ask your ISP to provide you most compatible DNS’s for you. Perhaps most known DNSs are 8.8.8.8 and 4.2.2.4.It helps you to browse the Internet more efficiently
Some people in other forums suggested that upgrading to Mountain Lion has helped them. But It didn't work for my clinic's line. Just changing the ISP at clinic resolved my problem
BETWEEN THESE 4 SUGGESTIONS, THE FIRST ONE IS THE MAIN SOLUTION AND NO 2-4 CAN HELP THE PERFORMANCE.
Move on!!!   Change your ISP and let me know if it works!!!!