Xbox Live Problem...HELP!!!

Ok whenever i TRY to connect to xbox live it wont let me. So I troubleshoot it and when it gets to the DNS it says it failed. I have my 360 hooked up to a router and the router seems to be working fine. I know there was a problem of not being able to get on XbL today but when i hooked my 360 directly up to my modem i was able to get on Xbox Live. SO can anyone can help it would be greatly appreciated

Thanks in advance