This may be caused either by an extension (a kind of Firefox add-on) or by your internet service provider. What happens is, the page you're loading requests something that is unavailable (like an image that has been taken down), and the add-on or ISP then diverts you to a search page to try to find that resource.

Here's how I suggest investigating:

(1) On the "DNS Solutions" page, look for a link on the right side or at the bottom that has anything like "About this page", "why do I have this page" or "opt-out" and click that link to learn what is causing it.

(2) Review/disable/remove potentially problematic extensions. You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Command+Shift+a (Windows: Ctrl+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. Then cast a critical eye over the list on the right side. Any system extensions that Firefox installs on its own are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious? If in doubt, disable.

Sometimes a link will appear above a disabled extension to restart Firefox before the change takes effect. You can complete your work on the tab and click one of the links as the last step.

Any improvement?

Since your MacOS 10.6 and your Firefox 48 are not being updated to address security issues, hopefully you have good security software to help protect against malicious add-ons or external software.