http://blogs.technet.com/tristank/archive/2007/06/18/kdc-err-badoption-when-attempting-constrained-delegation.aspxHit this earlier while working with someone else on a Kerberos delegation problem. All the SPNs looked right and were registered against the right accounts; all the App Pools were Network Service; from what I'd been told, everything should have been working...en-AUCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.technet.com/tristank/archive/2007/06/18/kdc-err-badoption-when-attempting-constrained-delegation.aspx#2573124Tue, 27 Nov 2007 18:36:23 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:2573124KDC_ERR_BADOPTION when attempting constrained delegation<p>PingBack from <a rel="nofollow" target="_new" href="http://feeds.maxblog.eu/item_1292686.html">http://feeds.maxblog.eu/item_1292686.html</a></p>