SetSPN

SetSPN is a command-line tool provided by Microsoft that is used to manage Service Principal Names (SPN) for Windows services in an Active Directory environment. SPNs are used in Kerberos authentication to uniquely identify a service instance on a network. The SetSPN tool allows administrators to view, modify, and delete SPNs associated with Active Directory service accounts.

SetSPN can list the SPNs registered to a specific service account in Active Directory. This is important for ensuring that services are correctly configured for Kerberos authentication. Administrators use SetSPN to add new SPNs to a service account. This is necessary when new services are deployed or when services are changed.

If an SPN needs to be changed or if it's incorrectly set, SetSPN can modify or remove the SPN from an account. Since incorrect SPN configuration can lead to Kerberos authentication failures, SetSPN is often used in troubleshooting related issues.

Some usage examples include assigning an SPN to a service account:

setspn -S HTTP/webserver.domain.com DOMAIN\ServiceAccount

Info

This command registers the SPN HTTP/webserver.domain.com for the specified service account. The -S parameter automatically checks for duplicates before adding the SPN.

Or listing SPNs for a service account:

setspn -L DOMAIN\ServiceAccount

Info

This command lists all SPNs registered to ServiceAccount.

You can even remove an SPN:

setspn -D HTTP/webserver.domain.com DOMAIN\ServiceAccount

Info

This command removes the specified SPN from ServiceAccount.

As an example:

In a company, an IT administrator sets up a new web application server webserver.domain.com that needs to authenticate users via Kerberos. The administrator assigns an SPN to the service account running the web service using SetSPN. This ensures that when users access the web application, the Kerberos authentication process can correctly identify and authenticate the service using the SPN.