Sorry guys I was not asking what the UA was. I know it was msn bot. What I am seeking is has anyone had the bot act in such an aggresive behavior that it acted like a DNS attack on the server. I had all three IP's hitting at the same time requesting 40-60 pages a sec. So in effect the bots were requesting 100 pages a sec or just about the entire website only on this website. We have 100 other domains on the same server and none of them were hit.
Forget the robots.txt file I blocked them from the firewall.