Opera’s user-agent spoofing
Because of this problem, the Opera browser identified itself in earlier versions as MSIE (Microsoft Internet Explorer), although the setting could be changed in the “Quick preferences” menu. Opera 9 now identifies itself as Opera by default. However, the user-agent string can still be changed via the “Site preferences” panel.
To find an example site for this article I went to Daniel Tobias’ page on the same topic: A Note on User Agent Identifiers and Browser Statistics. I then visited the PhotoDisc site with Opera 9.10 and took a screenshot of the rejection page (see below). When I returned with the user-agent string set to “Firefox” I was allowed into the site without a problem. Perversely, the site also let me in with Opera 8.5 while it was configured to send its true identity!
Notice that the site recommends Internet Explorer or Netscape Navigator/ Communicator. Today, very few people use even the latest version of Netscape, and Netscape Navigator disappeared under the radar before the end of 2002! There’s an email address on the page. No doubt lots of wry comments have been sent, but the outdated advice remains, making the maintainers look foolish. Perhaps by the time you read this, the site will have been fixed. Miracles do happen!
The screenshot below shows the “Site preferences” panel in Opera 9:
Two new options were added to Opera 9 — “Mask as Firefox” and “Mask as Internet Explorer” — which leave out the name Opera at the end of the string. Its true identity can be hidden altogether. There must have been sites that were deliberately excluding Opera, not simply looking for MSIE or Firefox identification strings. (Firefox/Mozilla users can download an extension that allows any user-agent string to be configured.)
Browser stats and Opera
So why does Opera now identify itself as Opera by default? That may have something to do with its poor showing in published browser statistics. TheCounter.com publishes global browser statistics on a monthly basis, and most other reliable sources report a similar market share for Opera. In theory, detection scripts could look for the Opera identification at the end of each string. But do they? Maybe that’s why the default setting was changed. Nevertheless, Opera can still mask itself so that it’s disguised completely. It may never be possible to discover how many Opera users have chosen that option.
