I'd start with having your network team analyze the traffic and see exactly what's going on. While awaiting that response, I'd search online for any issues with the various KB articles that are part of all your updates.
Thanks. I'll shoot some stuff off to my IT guys and see what they can see.
I did find some KB's but they were all about the certificate revocation list which takes roughly 15 seconds to time out so that was a big red flag, but they suggested blocking it at the firewall (which IT didn't want to do) or blocking it in the hosts file (which is what I ended up doing) but it made no difference.
Normally I wouldn't be too concerned about a 15 second delay, but we have some SQL jobs that have 30+ steps in them that are all smaller SSIS packages for moving and transforming data. That adds a lot of extra time onto a data load.
Thanks for the tip though; I'll poke the IT guys to check out the network traffic and see what is happening. If that doesn't help, I may need to look at increasing the complexity of our SSIS packages, but I don't like that solution.
Certificate revocation list? Sounds like something that you'd have to prevent from occurring at all, because I suspect that just blocking it doesn't do anything except keeping it from succeeding at all, and thus it times out. Not sure if that's something you can configure, or it's some security feature that is effectively blocked by some existing firewall rule on protocol or odd port number or some such.