Try adding the address to the local intranet:
In Internet Explorer, click Tools, and then click Internet Options.
On the Security tab, click Local intranet, and then click Sites.
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.
Click Add, click OK, click OK, and then click OK again to close the Internet Options dialog box.
Restart the computer.
This is a suggested workaround in the following Microsoft support article:
<a href=”http://support.microsoft.com/kb/303650″>Intranet site is identified as an Internet site when you use an FQDN or an IP address</a>