I wish I knew a better way to title this problem, so if anyone can think of a more appropriate title, please let me know. I've been banging my head on this problem for a little while, and usually I just work around it, but I felt it was time to ask for some help to get it solved.
Background
On our network, we keep a Webdav server which is located at intranet:8080 (10.0.0.2:8080). On this server our employees publish their Outlook calendars using the Share to Internet feature in Outlook. Within this folder is also a PHP file named index.php that lists off the calendars based off the employees names and provides webcal:// links (in the form of webcal://intranet:8080/Firstname_Lastname_calendar.ics) to the calendars to facilitate employees subscribing to each other's calendars.
We also have an Active Directory server at 10.0.0.1. The Active Directory server also provides DHCP for our network (setting itself as the primary DNS server and 8.8.8.8 as the secondary).
The Problem
One some computers when they click the links on intranet:8080 to subscribe to another employee's calendar they get an error message saying that Outlook "Cannot verify or add calendar to Outlook."
If I manually enter webcal://intranet:8080/Firstname_Lastname_calendar.ics (or even http://intranet:8080/Firstname_Lastname_calendar.ics) I receive the same error message. However if I enter webcal://10.0.0.2:8080/Firstname_Lastname_calendar.ics I do not receive an error message and the calendar is subscribed to.
This to me would appear to be an issue with DNS, but doing an nslookup on intranet returns 10.0.0.2 as provided by 10.0.0.1, and as we had previously seen, the web browser on the computer has had no issue accessing http://intranet:8080/ either.
As I said earlier, the issue doesn't happen on every computer in our network, and I've not really been able to work out a pattern for where it happens either. Any ideas? It would be fantastic for these employees to be able to easily subscribe to calendars without the IT department's help.
