Sub Domains don't work but subdirectories work fine?

Sub domains don't work?

[durgapuronline]

Can u please help me understand what the exact problem can be when I type [sub.example.com...] - which is not honouring my request but http://www.example.com/sub which works just as fine as I expected the former to work.

My sytem admin told me it a problem with my ISP, but it has gone beyond any tech logic where I can with the same ISP can surf sites with subdomains which I am requesting and getting results but not form the sample site I asked for.

Last week till saturday 1st. September it had worked fine and now for the last one week this problem has been a constant unsolved headache for my site and my system administrator is getting on my nerves now!

[edited by: Webwork at 6:18 pm (utc) on Nov. 6, 2005]
[edit reason] Example.com is the Domain Forum's domain of choice per Charter [/edit]

[Webwork]

Unfortunately this is the type of issue that often requires more disclosure then we care to embrace, such as your URL, DNS info, etc. Frankly, given the level of detail it's also the type of issue that is usually be addressed to your host, server admin, etc.