I use firefox for browsing, Ubuntu - 11.04 . Off lately it is behaving strangely. When i open a new instance of the browser, it opens random urls in new tabs which i have not visited before. Does any one know why this is happening ? Could it be a virus ? I thought Ubuntu was virus free. Are there any good antivirus software for Ubuntu ?
Lets try to debug this. If you start firefox from the terminal, and use a new profile, does the problem persist ?
If so, then the problem is more likely with your DNS or internet provider. Try using OpenDNS
If the problem does not persist in a new profile, then your user profile is either corrupt of perhaps a malicious script.
In that case, personally, I would make a new profile and use NoScript
Take a look at securing firefox
The IP address you posted belongs to a Japanese company called Accelia, which runs a Content Delivery Network. According to Google, none of the websites in their network are malicious.
Now, because you say it happens when you open a new instance of the browser, the first thing you should check is the start page. To do this, open Firefox and pick Edit -> Preferences from the main menu. In the settings window, check what is the current Home Page, and if it's something you are unaware of, then click "Restore to Default".
Let me know if it helps.