Linode Server Down

Can anyone help me, its very urgent

It depends what you're using your Linode for, and what software you've installed on it. It's possible that you might've installed something that was bundled with a rootkit or other malware, or it could be that a website you're running is insecure enough that someone might've slipped in a script/exploit that's able to run in the background.

This is the community, though, so very few here are able to see any information in your support ticket. Your best bet is to respond to the ticket to find out what type of malicious traffic has been reported (if there are anything in common with the traffic, aside from your Linode's IP address being the source).