[Web4lib] inability of browsers to differentiate DNS lookup failure from network connection failure

[John Fitzgibbon]

Hi,

Most, if not all, of the popular browsers do not distinguish between a
DNS lookup failure and a network connection problem.

For example, if you type a non-existent domain name into the address bar
of your browser the browser will return a page stating that either the
DNS lookup failed or there may be a problem with your network
connection.

If you disconnect your computer from the network and type a valid domain
name in the address bar of the browser you will retrieve the same page.

When DNS fails it returns a 'no such domain' message to the client but,
clearly this is not being communicated to the browser.

I'm sure there is a good reason for this, but, I am just wondering what
it is.

Any help would be much appreciated.

Regards
John

John Fitzgibbon

p: 00 353 91 562471
f: 00 353 91 565039
w: http://www.galwaylibrary.ie 

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