"myIpAddress" function returns incorrect result in Internet Explorer 9

Symptoms

Consider the following scenarios.

Scenario 1

• You configure Windows Internet Explorer 9 to use a proxy auto-config (PAC) file.

• The computer is connected to the Internet.

• You install an application on the computer that adds a virtual adapter. For example, you install VMware Player.

• The PAC file calls the myIpAddress function to retrieve the IP address of the network adapter that is used to access the Internet.

In this scenario, the myIpAddress function returns the IP address of the virtual adapter.

For example, you write the following function in the PAC file. In this situation, the myIpAddress function returns the IP address of the virtual adapter.function FindProxyForURL(url, host)
{
if (shExpMatch(myIpAddress(), "10.0.0.*")
{
//Bypass the proxy for URLs with-in the local domain
if (shExpMatch(host, "*.local.domain.com")) { return "DIRECT"; }

//Bypass the proxy when accessing local sites
if (isPlainHostName(host)) { return "DIRECT"; }

// Everything else goes through Proxy
return "PROXY 10.0.0.254:8080";
}

//Assume the computer is not at work.
return "DIRECT";
}
Scenario 2

• You configure Internet Explorer 9 to use a PAC file.

• The computer is connected to the Internet.

• You establish an additional connection to your corporate network through a virtual private network (VPN).

• The PAC file calls the myIpAddress function to retrieve the IP address from the VPN connection.

In this scenario, the myIpAddress function returns the IP address of the Internet connection.

Workaround

To work around this issue, write your own custom myIpAddress function for Internet Explorer 9. For example, you can write the following function:function myIE9IpAddress()
{
var ipex = myIpAddressEx();
if (ipex === false)
{
var myip=myIpAddress();
return myip;
}
var iparray = ipex.split(";");
for (j=0; j < iparray.length;j++)
{
var ipaddress=iparray[j];
//IPv6 adress : skip
var parts=ipaddress.split("::");
var firstpart=parts[0];
if (firstpart==="[fe80")
{
//alert("skipping IPv6 address :"+ ipaddress);
continue;
}

//IPv4 address starting with 192.: skip
parts=ipaddress.split(".");
firstpart=parts[0];
if (firstpart === "192")
{
//alert("skipping IPv4 address starting with 192. :"+ ipaddress);
continue;
}
break;
}
return ipaddress;
}

Resolution

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
 

824684 Description of the standard terminology that is used to describe Microsoft software updates

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

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