HL said:
I have to enable 'Use a proxy server for your LAN' when using my laptop at
work and I have to disable this option when at home. It's really tedious
having to click on Tools/Internet Options/Connections/LAN Settings to access
this feature.
Is it possible to create separate shortcuts to IE - one with 'proxy server
enabled, and one with 'proxy server' disabled?
Thanks
http://support.microsoft.com/kb/271361
Have your IT folks provide a wpad.dat file that IE can grab if found
which would configure IE to use the company's proxy when you are on
their network. This script gets used when you enable the "Automatically
detect settings" option in IE. I'm not sure from where IE gets the
wpad.dat file for the script. Maybe it is part of the web server setup
mentioned for the virtual folders (defined by those names under the
webroot but can be physically anywhere).
When you are at home, IE won't be able to find this file when you
connect to the host so no proxy would get used. You may have to logoff
and then back on to eliminate the proxy caching within a Windows
session; however, it is likely that the hosts you visit at home won't be
the hosts you visit at work (unless you're using a direct connect to
their network from home, like over VPN). They could use substring
matching inside the FindProxyForURL() function to let it effectively
wildcard on any of their internal hosts (by IP name or IP address) or
they could check in a lookup table. Writing the script would be up to
your IT folks.
You can also use the "Use automatic configuration script" option in IE
under the Connections tab, LAN settings. You specify the UNC of where
to find the script file so maybe it could be local (if your IT folks
won't or can't do it). In fact, a local path would be needed to find
the script when you are not on the corporate network; however, I would
think if it were on a corporate host but you were at home so the .pac
file couldn't be found then no proxy gets used (unless, of course, you
defined a proxy under the "Use a proxy server for your LAN").
Normally WPAD is disabled in IE for home or non-corporate users because
it can cause delays sufficient to generate errors, like a gateway
timeout error. The usual advice to disable WPAD (Web Proxy
Auto-Discover) in Internet Explorer is:
- Internet Options -> Connections -> LAN
- Disable 'Automatically detect settings'
Regarding WPAD, read:
http://support.microsoft.com/kb/307502
http://www.vnunet.com/vnunet/news/2204911/microsoft-warns-vulnerability
http://www.microsoft.com/technet/security/advisory/945713.mspx
http://perimetergrid.com/wp/2008/01/11/wpad-internet-explorers-worst-...
I have had that option disabled for many years. I don't use web proxies
and don't remember ever having an ISP that hooked me up to one. I don't
recall ever being at a company that made me use one, either. There is
no point to do the multitude host searches trying to find a WPAD server
when there isn't one. It can cause a "gateway timeout" error in IE
because it took too long to find a WPAD server (that does not exist).
The WPAD functionality is documented in the IEAK (Internet Explorer
Administration Kit).
Googling find several possible help articles:
http://www.google.com/search?q=+"internet+explorer"+%2B"automatic+configuration+script"
like:
http://nscsysop.hypermart.net/proxypac.html
My guess is that these instructions (for the first example function) are
assuming that you get 192.168.x.x from your router's DHCP server while
at home and get some other IP address when on the corporate network.
However, it doesn't test for a range of IP addresses, like 192.168.1
(leaving off the last octet) depending on the configuration of the DHCP
server inside your router and what range of IP address its DHCP server
will assign assuming you don't give your hosts static IP addresses (not
likely if you're taking the host to work). Personally I would test if
the host was NOT on the corporate network since there would probably be
fewer IP ranges on which to test. If your host isn't at home but
travelling with you then you will get whatever IP address at the hotel,
cafe, or bookstore that you happen to visit to use their wifi or hookup.
It looks to be C-like coding to write the scripted function.
So it is doable. Once setup it would be automatic. The hard part is
writing the script. Since your company requires the use of a proxy to
access their internal hosts (sounds dumb to me) you might be able to
pass the buck to the IT folks to get them to give you what they consider
is a sanctioned WPAD script.
