Introduction

I have seen a weird problem in DNS last week. One of my colleagues was asking a host (A) record in all uppercase. I am not sure why that is required because Microsoft DNS is not case sensitive. The colleague told that is required for SAP but I don't have the clear idea about that requirement. I needed this to work with an existing  "A"  record which is already in all lowercase.

I deleted that record & recreated that in all uppercase but problem was not solved

Symptoms:


Existing Host record called "kobi"


Deleted the "kobi" & recreating the "KOBI"

And see the wired result in the below snap.

Automatically that turns in all lowercase because same previous record was in all lowercase.
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Solution

I have deleted that record from DNSMGMT.msc but the issue was not resolved. Then I have created a NEW record in DNS with all CAPS & not found any issue with that. Deleted that & recreated; that seems in all uppercase. Now I came to the conclusion that it might be the cache issue or still that record is present somewhere else. Yes; in test environment I have found that record in adsiedit but not found in production environment. Due to LDAP policy; we are able to see only 10000 record in adsiedit so I used sysinternal adexplorer for deleting that record in production. Ldap policy is not effected the sysinternal adexplorer so I can see the "A"(kobi) record in ADExplorer.

See more about Ldap Policy: http://social.technet.microsoft.com/wiki/contents/articles/14559.active-directory-ldap-policy.aspx

See the below snap from adsiedit after deleting the "A"(kobi) record from DNSMGMT.

See the below snap from ADEXPLORER after deleting the "A"(kobi) record from DNSMGMT



Download ADExplorer from Microsoft site.
http://technet.microsoft.com/en-us/sysinternals/bb963907.aspx

Delete that record from adsiedit/ADexplorer & restart that server & run repadmin /syncall /aepd. Next day you can create that record.