When did 127.0.0.1 become different than localhost?

[Joseph Geretz]

When did 127.0.0.1 become different than localhost?

I think this happened around the same time as SP2 when Microsoft got the
idea that it might be a good idea for them to get into the Security /
Firewall business. NOT!!!! Why the @#@^$#^&&* does 127.0.0.1 produce a
different effect in certain circumstances than localhost?

For example, I've got a Visual Studio Web project which defines the path to
the project file as http://localhost/MyApp/MyApp.csproj. This works on my
workstation, but when I ported this over to another developer's workstation,
Visual Studio was unable to open the project. After fiddling around with
this for some time, I discovered that http://127.0.0.1/MyApp/MyApp.csproj
would work on that workstation. What is this about? Aren't localhost and
127.0.0.1 supposed to be the same thing? How can I loosen up (security?)
restrictions on that box so that localhost access will work?

Thanks for your help!

- Joe Geretz -

 

[Yves Leclerc]

When did 127.0.0.1 become different than localhost?

I think this happened around the same time as SP2 when Microsoft got the
idea that it might be a good idea for them to get into the Security /
Firewall business. NOT!!!! Why the @#@^$#^&&* does 127.0.0.1 produce a
different effect in certain circumstances than localhost?

For example, I've got a Visual Studio Web project which defines the path to
the project file as http://localhost/MyApp/MyApp.csproj. This works on my
workstation, but when I ported this over to another developer's workstation,
Visual Studio was unable to open the project. After fiddling around with
this for some time, I discovered that http://127.0.0.1/MyApp/MyApp.csproj
would work on that workstation. What is this about? Aren't localhost and
127.0.0.1 supposed to be the same thing? How can I loosen up (security?)
restrictions on that box so that localhost access will work?

Thanks for your help!

- Joe Geretz -

You host file may have been affected by some type of malware. Or you may have
a DNS resolution problem.

 

[Malke]

When did 127.0.0.1 become different than localhost?

I think this happened around the same time as SP2 when Microsoft got
the idea that it might be a good idea for them to get into the
Security / Firewall business. NOT!!!! Why the @#@^$#^&&* does
127.0.0.1 produce a different effect in certain circumstances than
localhost?

For example, I've got a Visual Studio Web project which defines the
path to the project file as http://localhost/MyApp/MyApp.csproj. This
works on my workstation, but when I ported this over to another
developer's workstation, Visual Studio was unable to open the project.
After fiddling around with this for some time, I discovered that
http://127.0.0.1/MyApp/MyApp.csproj would work on that workstation.
What is this about? Aren't localhost and 127.0.0.1 supposed to be the
same thing? How can I loosen up (security?) restrictions on that box
so that localhost access will work?

Microsoft SP2 did not change localhost from 127.0.0.1. Something on your
computer is amiss. Check with the Visual Studio Web tech support for
why you are having difficulties with their software. I'm not sure what
you mean by "ported this over" since porting software usually means
re-coding it to run on another platform/operating system.

You will have to examine any third-party security software you have
installed to see if a proxy is in use.

Malke

 

[Guest]

......and since it may be the Hosts file, you should first take a look at it.
If you don't know, it's located in Windows\System32\Drivers\Etc. Open it
with Notepad and confirm that the only line in it (other than ones that are
preceded by "#") is "127.0.0.1 localhost". If there are any other
entries, confirm that they're there for a good reason, otherwise delete them
or precede them with "#". If "127.0.0.1 localhost" isn't present, add
it.

 

[Steven L Umbach]

No they are not exactly the same thing. Localhost is a human friendly name
that resolves to 127.0.0.1 and by default is the only entry in the hosts
file in the operating system. If the hosts or even lmhosts file is changed
127.0.0.1 can resolve to any name. Actually Windows firewall products such
as Windows Firewall and ISA 2004 work very well if configured
operly. --- Steve

 

[cquirke (MVP Windows shell/user)]

On Thu, 19 Jan 2006 11:00:58 -0500, "Joseph Geretz"

When did 127.0.0.1 become different than localhost?

I think this happened around the same time as SP2 when Microsoft got the
idea that it might be a good idea for them to get into the Security /
Firewall business. NOT!!!!

Actually, they HAVE to be there, and it's WAY overdue!

Imagine you move into a new neighborhood, and, eager to please, you
tell all your neighbors; "drop in whenever you feel like it, here are
keys to the house, don't be a stranger".

After a while, you start to notice things going missing around the
house, then cigarette butts and used syringes lying around, and
finally when you find human turds in the sink do you realise you need
some security clue after all.

But you don't want to offend your "friends", so you make excuses even
as you try to regain your privacy; "sorry you have to knock on the
door, I lost the key and had to change the locks and only have one
that fits, don't be a stranger, you're still welcome, but knock first"


So it was when MS brought out IE4 to compete with Netscape. It was
"Hell, if Netscape lets you drop cookies and JavaScript your visitors'
PCs, we'll give you even stronger tools like ActiveX so you can like
totally OWN their PCs! Develop for IE today!!"

Now SP2 is trying to stuff Pandora back in the box.

Why the @#@^$#^&&* does 127.0.0.1 produce a
different effect in certain circumstances than localhost?

IE's security model works as a set of zone contexts; Restricted,
Internet, Intranet, Trusted and My Computer (local HD). Before, My
Computer zone was wide open; if you'd made it as far as the local HD,
you could do what you like. SP2 changes that slightly; there's an
awareness that because it's so easy to attain access to this zone, one
has to limit what can be done in this zone too.

Asyou say, whatever zone policy applies to localhost should apply to
127.0.0.1 too, so the variance is worrying. Either there's no
localhost=127.0.0.1 in the HOSTS file, or you may have hit some other
hassle. I know that SP2 has created problems where 127.0.0.x (where x
is not 1) were no longer treated as localhost, breaking some printers.

For example, I've got a Visual Studio Web project which defines the path to
the project file as http://localhost/MyApp/MyApp.csproj. This works on my
workstation, but when I ported this over to another developer's workstation,
Visual Studio was unable to open the project. After fiddling around with
this for some time, I discovered that http://127.0.0.1/MyApp/MyApp.csproj
would work on that workstation. What is this about? Aren't localhost and
127.0.0.1 supposed to be the same thing?

I think they are "the same thing" only by vrtue of a definition
usually found in HOSTS. HOSTS is comonly attacked by malware and thus
may often be renamed away or wiped, so it would be introducing a
needless fragility to rely on localhost when you could use 127.0.0.1

How can I loosen up (security?) restrictions on that box so that
localhost access will work?

You don't - especially if developing sware for use on arbitrary PCs.
You don't want to say "our software requires you to drop your knickers
and bend over", nor do you want to create a fragility that has your
service agents wading through "how to check that localhost is defined
in HOSTS" on every "it doesn't work" support call

---------- ----- ---- --- -- - - - -

Don't pay malware vendors - boycott Sony

 

[Kerry Brown]

You don't - especially if developing sware for use on arbitrary PCs.
You don't want to say "our software requires you to drop your knickers
and bend over", nor do you want to create a fragility that has your
service agents wading through "how to check that localhost is defined
in HOSTS" on every "it doesn't work" support call

A very good point. Perhaps they could set a variable with %COMPUTERNAME% and
use that instead of localhost. There's probably other options as well.

Kerry