Kerberos and NTLM


We are using Windows 2003 AD.

We have many different applications, and some need to authenticate to AD using either Kerberos or NTLM.

Could someone please clear a few things up for me -

i. Which one is the 'preferred' authentication mechanism - Kerboros or NTLM?

ii. MS products such as Outlook, SharePoint etc - which one do they use?

iii. If I used a product like Wireshark for example, is it possible to see which authentication mechanism was being used?

iv. Are there any benefits to using Kerberos over NTLM (or vice-versa)

v. Which one is the 'newer' protocol?

vi. Can their ports be changed?
Who is Participating?
Mike KlineConnect With a Mentor Commented:
Kerberos is preferred and default

They should be using kerberos for AD authentication

You can use a network sniffer but take a look at these two articles from the askds team...not easy to audit NTLM.  It should also help with your questions.


redman20111Author Commented:
Hello Mike

Thanks for the if we had an application that used NTLM to authenticate, what are the downsides of that for us? Should we push the vendors to utilise Kerberos?

Or are there any advantages of NTLM over Kerberos?
Mike KlineCommented:
I can't think of NTLM advantages.   Yes push vendors to use Kerberos and if they can't ask them why not.   They have had plenty of time...the blog below is from 2006


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