Ah – another bug-ette, unfortunately. It seems that if you are using a Websense server for your URL filtering, and the websense server goes away for a while (e.g. while it reboots), the SRX doesn’t bother re-connecting.
There’s a timeout you can set, and I’ve not tried that yet, but it has been verified by JTAC as happening within a few minutes.
What’s disappointing about this is that there’s no way in Junos that you can specify a secondary server – you can’t do that in the feature-profile or with a second policy. So in a way, the timeout doesn’t make any sense: there’s no second option to fall back onto.
The disconnect is going to be fixed in 10.1R2, and might be available via a special engineering build if you press hard enough. I plan to log the ‘backup server’ idea as a feature request.