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Intranet site is identified as an Internet site
http://www.vistaarticles.com/articles/169/1/Intranet-site-is-identified-as-an-Internet-site
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Published on 11/23/2006
 
When you access a local area network (LAN), an intranet share, or an intranet Web site by using an Internet Protocol (IP) address or a fully qualified domain name (FQDN), the share or Web site may be identified as in the Internet zone .

Intranet site is identified as an Internet site

1. In Internet Explorer, click Tools, and then click Internet Options.
2. On the Security tab, click Local intranet, and then click Sites.
3. Click Advanced, and then type: *.domain.com or an IP address range (for example, 157.54.100-200.*) in the Add this Web site to the zone box, where domain.com is your company and top-level domain names.
4. Click Add, click OK, click OK, and then click OK again to close the Internet Options dialog box.
5. Restart the computer.

Details: http://support.microsoft.com/kb/303650/en-us?spid=2073&sid=global