Weird traffic boost. Is it a DDoS attack?

[XYZ500]

I've opened my forum and noticed something very weird. The section (forums) viewing numbers that are shown after the section's name, for example, "vB4 General Discussions (14 Viewing)" on this forum. I'm talking about this. This viewing numbers are exceptionally high. This can't be natural traffic. The viewing numbers have been multiplied by 5, 6 times on all sections. The Google Analytics real-time traffic shows only 3 visitors on the site right now. Usually the online guests number shown under 'Currently Active Users' is around 1000-1500. Right now its at 5500. What's going on? Is this a DDoS attack? or some kind of other attack?

[kh99]

Hmm...did you do anything like increase the session timeout value?

[XYZ500]

Hmm...did you do anything like increase the session timeout value?

No, I did not make any kind of changes. I contacted my host as well to see if the site was under attack. They tell me they don't see any excessive traffic on their graphs.

[SaN-DeeP]

If you have root check yourself.. using putty.. or

[RichieBoy67]

It is most likely search engine bots. Check your server connection logs though to be sure.

[thetechgenius]

Thats normal for most forums these days, its just Search Engine Spiders, and probably Spam Bots trying to gain access to your forum to post spam.

Are you getting a lot or any spam posts on your forum?

If you are, I suggest following Ozzy's guide to stop spam bots in vBulletin - http://ozzmodz.com/showthread.php/506-The-Era-Of-Big-Spam-Is-Over?