Here’s the scenario- a large network (in this case, a mix between Novell and Active Directory) is having DNS issues from various causes (welcome to being in a Novell network).
Now normally this isn’t a huge deal because the client is still able to query DNS and everything works. DHCP is working properly. The problem mostly shows up in XenDesktop because your DDC will send a login to a machine and it’ll hang.
Skills Required:
Working knowledge of DNS, TCP/IP and optionally DHCP in your environment. This exercise does not require server access. If that’s too much to ask, you’re on your own 
Software Required:
Windows machine with standard IP tools installed (nslookup, specifically)
Microsoft Excel (this was tested in Excel 2003)
Here’s what I did:
- Enter Command Line (Start -> Run->cmd)
- Navigate to the directory of your choosing- this is where the output file will be saved – for example, c:\test
- type nslookup
- You’ll see the > mark to indicate nslookup is ready for a command
- (optional) if you are wanting to drill down detail from a specific DNS server, enter server x.x.x.x or server.domain.net
- type ls –d your.domain.here > file.csv
Now there’s the problem of how to analyze this data.
- First, open the .txt or .csv file in Excel - you’ll be prompted for the usual import stuff if you are importing a text file.
- Find the bottom of the sheet to know how many rows we have. In this example, we will use 2000 as our number.
- Select the first column
- Click Format ->Conditional Formatting
- Choose ‘Format Is’ from the dropdown
- Enter =COUNTIF($A$1:$A$2000,A1)>1
- Click Format to choose how to announce duplicates. In this example, I’m using Bold font and a Red pattern
From there, you can see highlighted the duplicate addresses. Of course, in my example, there are 2000 IPs.
It’s easy enough to delete multiple entries in Excel. But how do we remove the addresses that are NOT duplicates to generate a usable report? Thus far it’s just been a matter of pulling the rows into another sheet or deleting the rows with non-duplicate data. With 2000 rows, it’s not fun.
With that in mind, I’m still working on that- tune back in soon to find out what I came up with!
