confused over DNS

[Longy]

I'm missing something simple here but I don't know what:

If I ping a website and get the IP and put the ip into a web browser it should still load the webpage correct?

eg: I ping google.co.uk get a IP of 216.239.59.104 I paste that into web browser it loads google.

But when I ping a certain website and load it's ip into a browser it says 'Site not found'

is it a rDNS issue? shouldn't need DNS surely as its just an ip?

edit: sorry should have said - all websites work with typing the name of the site. The problem I have is with a customers website I'm changing the NS servers on.

 

[Dafthead]

reboot your router, sorts the issue 9 times out of 10

 

[Longy]

unfortunately its not a local router issue more webserver issue I feel.

The customers domain registrar (fasthosts) has had its NS servers changed to easydns.net - as I dont have access to the easydns.net account I need to change the NS servers back to the registrar fasthosts but I'm gonna have to set up the DNS records again for the MX and www. but the ip of the www. A record is pointing too won't load the website but www.thedomain.co.uk does :/

 

[PinkoCommie]

Some webhosts use the Host http header to re-direct you to a virtual host, so if you just try to connect to the IP address on its own it doeesn't know what to do with the trafffic so either drops it, or re-directs to a holder page or different site.

For instance, if www.dogs.com and www.cats.com both resolve to the same IP address through DNS, when you connect to either of these sites, the HTTP headers will show:

GET / HTTP/1.1
Host: www.dogs.com

or


GET / HTTP/1.1
Host: www.cats.com

So even though the request goes to the same IP address, you get a different page/site served to you from a different virtual host.

It allows hosting companies to use 1 IP for multiple websites.

What you could try to test is to set the IP address and domain name in you local hosts file, then put the somain name into your browser, it will then resolve locally to the correct IP and you will have the correct host header so the webserver knows what to do with it.

Not sure if this is what you need, coz I'm a bit stoned

 

[DMS]

The host's web server might not be configured to respond to HTTP requests in the form of an IP address.
If it's a web server that hosts multiple websites it'll most likely use host headers to determine which site to serve. It does this by reading the HTTP headers and using some form of logic, or a pre-configured virtual directory to determine which site to serve.
216.239.59.104 will load Google's homepage because the server hosting that website is most probably doing nothing else but host that. Google is a very high volume site, so it'd be stupid running it on anything other than a dedicated web server. They've no reason not to allow the IP address in a HTTP GET request.

 

[DMS]

Poo. Pinko got there before me lol.

 

[Longy]

ahh yeah get you - so they are multi-homing websites. So if a set the DNS A record for www. to the IP it should carry on to work? which I can test with pinko's idea

cheers guys

 

[DMS]

Yes.
Bear in mind that a DNS record can take anything up to 72 hours to propogate around the interweb though.
If you edit your "hosts" file so that the www address points to the IP address of the web server it should prove that there's no DNS issue, and that the DNS changes just haven't propogated yet.

 

[Longy]

yeah just tested it pointed it to 127.0.0.1 to make sure it was reading the host/lmhost file correctly then put in the correct IP and it worked.

I've not changed the NS servers yet but at least I now know when I do, the website will still be there

 

[PinkoCommie]

yay! I knew I had my uses