https://support.opendns.com/entries/23553235-How-do-I-Disable-OpenDNS-Completely-

Also please update to Firefox 28. Thanks!

Do you mean:

(1) When you try to go to www.ask.com you get a screen indicating that it is blocked, or

(2) When you search in the address bar, instead of getting results from Ask you get results from OpenDNS.

For #1, OpenDNS offers filtering services for home users (parental control) and business users, but I don't know why ask.com would be blocked. ?!

For #2, if you enter a one-word search into the address bar, Firefox will look it up as a possible server name and if it doesn't exist, then OpenDNS may jump in and point Firefox to its search results.

If that results page does not let you opt out of this service, you could consider switching from OpenDNS to a different DNS service. Rather than guess how your network is set up, if you need to know more about that, please describe your setup.