Websphere ND dmgr permission problems

Ran in to a really weird problem with one of our Websphere 6.1 Network deployment setups yesterday and as I couldn't find one single page about the problem in google I thought I'd blog it.
I'm not much of a Websphere admin but managed to fix it after a while.

The problem started when a datasource was updated and all of the sudden all node agents stopped trusting the deployment manager (dmgr). Syncing the nodes failed and hence pretty much everything failed to restart / deploy. Running servers where fine though.
We got this message in the logs:

[1/17/08 13:30:52:020 GMT] 00000028 RoleBasedAuth A   SECJ0305I: 
The role-based authorization check failed for admin-authz operation 
SSLAdmin:temporarilyDisableCertificateAuthentication:java.lang.Long.
The user UNAUTHENTICATED  (unique ID: unauthenticated) was not granted
any of the following required roles: administrator.

My best guess is that node agent configuration was corrupted in some way.
How do you fix the problem then?
Fairly easy actually.
# Stop all node-agents that seem broken (that would probably be all of them!).
# Go to the node agents bin directory on the node (usually something like $WAS_HOME/profiles//bin/).
# Manually sync the node with syncNode.sh, point to the SOAP connector (default is 8879) on the DMGR server. See example

./syncNode.sh dmgrhost 8879 -username websphere -password webfear

# Start the node agent and verify that the logs are happy. Kick off a cell sync from dmgr. You should see entries similar to this in the logs:

[17/01/08 16:14:59:872 GMT] 0000002f NodeSyncTask  A   ADMS0003I: 
The configuration synchronization completed successfully.