CODEWITHSUNDEEP
sql-serverauthenticationkerberosntlmkerberos-delegation
AndreaD
AndreaD

Reputation: 11

Double Hop when Linked Servers are on Same Server, Client on Diff Server?

I'm trying to solve a mystery. We have two SQL Server instances residing on the same server. SQL instance A is linked to SQL instance B. Connections are made using pass through authentication. The calling service is on a different server. No settings were put in place for Kerberos delegation, no SPN, no trust for delegation, etc. However, we weren't getting authentication failures when running distributed queries through the linked server connection. This makes no sense to me unless having the two instances on a single server results in a single hop scenario (from calling client service to server on which both instances reside). The underlying Kerberos config is now in place, so Kerberos is being used successfully, I'm just trying to understand how the connection would have worked before I made the necessary changes. Does anyone have any insight into this? Thanks.

Upvotes: 0

Views: 509

Answers (1)

Remus Rusanu
Remus Rusanu

Reputation: 294407

The number of 'hops' is given by the number of distinct 'Local Security Authority' involved. When you had two SQL Server instances on the same machine there was only one LSA involved, so no delegation was required.

Upvotes: 2

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