Friday, November 9, 2007

WCF Security Exception: Timestamp is invalid because its creation time is in the future

Well, I ran into a real fun bug today that surfaced itself on the user's computer as a "Security Exception see Inner Exception". Upon examining the inner exception, it told me that the message was incorrectly secured. After placing some tracing on the server, I found this error message:

The security timestamp is invalid because its creation time ('11/9/2007 10:37:07 PM') is in the future. Current time is '11/9/2007 10:28:52 PM' and allowed clock skew is '00:05:00'.

After fixing the user's clock, which was roughly 8 minutes fast, everything worked great. The next question is "How do I increase the maximum skew time"? It took a bit of searching to figure out that I need to create a custom binding to change the values. Here is an example of how to do it:

<binding name="MaxClockSkewBinding">
<textMessageEncoding />
<security authenticationMode="Kerberos">
<localClientSettings maxClockSkew="00:07:00" />
<localServiceSettings maxClockSkew="00:07:00" />

<secureConversationBootstrap />
<httpTransport />

For more information, see How To: Set a Max Clock Skew on MSDN.

More References:


Anonymous said...

Extending the clock skew is the wrong answer. The local time needs to fixed by using ntp pointed at time server. Preferably at the DC issuing the kerberos ticket.

Dave said...

My issue is not that our servers are out-of-sync. The problem is that our many USERS on their home computers or laptops are not using a time server.

Anonymous said...

right one Dave ... there's gotta be an option to disable the timestamp check all together. MSFT??