We currently have the following setup:
2 Domains companya.com and companyb.com, each with externally hosted websites.
companya.com works perfectly however companyb.com is a newly acquired domain and has been added to our internal DNS. In the forward lookup zone for this DNS entry we have 'A' records for mail and www (pointing to external IP address of website - IP is definately correct)
mail.companyb.com works perfectly and other prefixes; its only the www that wont seem to work. In IE you get back a HTTP 403 forbidden page
Any ideas? Hoping you can help