Can't access websites, "URL not found on server"?

Are you behind a router? This looks like your port 80 may be shut

80 is http used by web traffic

Go to Finder >> Applications >> Utilities >> launch NEtwork Utility >> go to Port Scan and run the scan

Tell us what do you see for the 80 port? TCP port open?

It could be the site, your ISP, your router or your Mac.

jeng4 wrote:

When I run the scan do I enter the IP address that is displayed under the Network? Because when I enter that number and run the scan it says that it can't find the host..?

I don't see/know where to find the 80 port? What is the TCP port?

Start Network Utility

• Go to Info tab - see what IP address you have under the Interface Information
• Go to Port Scan tab
• your IP should be preset and shoulod match the one from above, if not enter it manually
• Don't check the checkbox for only scanning certain range
• Hit Scan
• 80 must be open for your web browser to work

Send over the exact hyperlink of a site(s) you are having trouble with,
that way we can rule out that the error is on the server end

• Do you have other computers in your house on the same network?
• Could you try to go to that website from a different computer and see what happens?

Just trying to narrow down our options here...

IP address

Is how your computer is identified on the network. It's almost like a house and ZIP address for a house - it's unique on any given network

If you are connected directly to the internet (for instance), it will be a public IP which others can reach, such as 123.456.78.90

If you are behind a router, the router will take over the public IP (123.456.78.90) and assign your Mac a private IP, for instance 10.0.1.2, which is visible only to the computers on your private network created by the router, but to nobody outside on the internet.

TCP port

Is a Transmission Control Protocol. It is a protocol which unifies how computers talk to the outside world, to say it bluntly. It is like a door to / from your computer.

So, you computer has an IP address which is almost like a house address and a zip and a country code - it's unique to every PC on the network.

Your TCP ports are like a bunch of doors going in and out of your house - in order to use them, they must be open. Each door serves a different purpose.

There is a door #80 for internet browsing, there is a door #22 to make secure connections to other computers, there is a door #21 for sending files via FTP, there is a door #25 for your e-mails, door #5298 for your instant messaging, etc....

The same address and door logic applies to anything on the net, including your router. So, if you have one, you have to make sure it has the right ports open and that there isn't something what keeps opening or closing them on a schedule or randomly.

OK, so port is open on your Mac.

Next step:

• What Mac are you running on and what OS X version?
• What browser are you running on?
• Have you done any Software Update lately?
• How is your Mac connected to the internet?
• Any router or Wifi between your Mac and cable modem? If yes, make and model?
• Do you have any other browser to try?
  http://www.mozilla.org/en-US/products/download.html
  https://www.google.com/chrome/index.html
• If you tried any of the above, do you still get the same error?

Let's see what's next after these questions.

JK>

the site I am having trouble with is http://www.adobe.com/ my friend was over here using her computer on my network and she was able to access the website on her own computer.

Well, that sure eliminates the DNS theory...

Can you try logging into the GUEST account, and then letting us know if Safari from there can see it?

OK, so no wifi, it's not your ISP, since your friend could see the pages on your network, so now we are truly focusing on your Mac and nothing else.

I like Hackintosh's suggestion on you trying a different account.

I was going to suggest 3 things:

1. Create a brand new account on your Mac - make it an administrator, log into it and try Adobe.com
2. In Safari, turn on private browsing and try the site again
3. If you get the error on Adobe, can you go on Safari to Menu >> View >> View Source and show us what you get? I'd need to see the source code of the error page, I think.

Have you tried to completely RESET Safari in its Menu, bu any chance??

When you click Reset Safari 5.1.x in its menu it will show you a window with checkboxes for all various things you can reset.

It wil not delete your bookmarks nor will it wipe your passwords from Keychain.

It will clean your history, cookies, forms, passwords stored in Safari, top sites and a bunch of other junk.

When I reset it, I check all the boxes.

I reset periodically, just to clean out my HDD - the internet files can take a ton of space and slow things down.

Your Mac is not under Apple Care or warranty by any chance, is it? I'm kinda runnin gout of ideas after the reset. I've got two more left:

1. Nothing short of reinstalling Safari from the ground up.
2. Disk Utility under Applications >> Utilities
   Choose the startup disk where your OS is lcoated and Reapir Permissions on it - they can cause the weirdest errors and problems, sometimes even unrelated.

There is a third one:

I see that you have a MBP. Could you take it to your friend's house or Starbucks or something and try it over their internet connection? That would 100% confirm that it is NOT your modem or FW setting