Hello,

I cannot run asp.net web sites using the asp.net development server. It keeps giving me

"The page cannot be displayed", but if I write 127.0.0.1 instead of localhost it's working.

(Vista Ultimate, Visual Studio 2008 SP1)

Any ideas?

Yes, Its probably down to your hosts file here:

c:\windows\system32\drivers\etc

Open the HOSTS file

make sure this line exists

127.0.0.1       localhost

That's my HOSTS file:

# Copyright (c) 1993-2006 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
#      102.54.94.97     rhino.acme.com          # source server
#       38.25.63.10     x.acme.com              # x client host

127.0.0.1       localhost
::1             localhost

?

Yeah thats fine.  That file is responsible for mapping localhost to 127.0.0.1.  Try flushing the dns?  in a command prompt type ipconfig /flushdns  (right click command prompt > run as administrator)

Not working...

Any other idea?

try cmd > nslookup localhost 

That should return 127.0.0.1 if it doesnt then it cant resolve the name

Server:  UnKnown
Address:  192.168.1.1

*** UnKnown can't find localhost: Non-existent domain

Yeah thats the problem!I  DNS cant resolve the name you have in the hosts file for some strange reason.  Not sure of a solution to be honest.. might be a google job? last resort:

In IIS Manager, Can you check if the website is set to "All unassigned" or IP address? Try using "all unassigned" First, if that does not work - Try using IP address.

But I am using the ASP.NET Development Server?

matanm123:

But I am using the ASP.NET Development Server?

I forgot about that! 

 Do you have a firewall or something like Norton Internet security that could be interfering with that?

ESET Smart Security?

May be, not sure what that is to be honest!  Try disabling things like that and the windows firewall.  When (if) it starts working then you will know what application is causing the problem!

Yup, that was ESET.

Thank you very much for your help!

Hi David,

I am also getting the same Problem...! According to you...My application may be contain some Harmful code?

How can found Harmful code. 

man...THANKS!

u dunno how much u helped...i've got a project to present in 36 hours and this problem sucks and i couldnt even start working

never heard abt this host file config

God bless u