Two nights ago we removed a Juniper Netscreen SSG 5 and replaced it with a Juniper SRX 210. The company that performed the install tested everthing on their computers and the internet was accessible for them on our network so they called it a night and went home.
When we got in yesterday, some websites were available and some weren't. Strangely microsoft.com wasn't available. This made us think Conficker worm or DNS problem. After checking for both of these issues and determining that this wasn't the cuase, we thougtht that perhaps the problem was corrupted ARP tables on the Juniper or our switches. We rebooted every device on the system including all servers and networking infrastructure.
After all this the same random sites were not available.
The strange thing in all of this is that any device that was placed on the network prior to the Junpier SRX install is not able to access the random sites I noted above. The two computer consultants whose computers had never logged into our network until after the Juniper box was installed could access any site they wanted.
We are totally stumped. We can access some websites but in other cases we can't.
Any suggestions would be really appreciated