MSIE 7 prefetch

XP and Vista prefetch with MSIE 7

[dstiles]

Further to other threads about prefetch by AVG/etc:

I'm seeing a lot of UAs beginning...

User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; ...

This is coupled with HTTP_X_MOZ=x_prefetch so I'm assuming there is a prefetch enabled within MSIE 7. Same thing in both XP and Vista but only, as far as I can tell so far, in MSIE 7.

Now getting my standard "we don't do prefetch" page instead of a simple "go away" 403.

Since the "User-Agent:" prefix has been used by bad bots in the past this is (again) a bad idea for a UA.

[Samizdata]

My immediate thought is that what you are seeing is the IE7Pro plugin, which is known to corrupt the user-agent string in that way (accidentally) and which is apparently popular with some people.

You have to be careful when you intercept (rather than 403) accelerators as they may cache the first page you serve, which can make it difficult to subsequently serve the real content - and you may find that any links on the "intercept" page simply send you round in circles.

I would suggest installing Google's Web Accelerator temporarily to test your methods.

...

[keyplyr]

Interesting, this is the first I've heard of IE doing this. I continue to filter "User-Agent" and "User_Agent" since I get a lot of East Europe scrapers. Looks like we're not through with this yet.

[dstiles]

Samizdata - thanks for the info.

Not being a user of Internet Exploder (and in any case not being able to install IE7 on Windows 2000) I have no way of testing IE7 for anything except very rudimentary tests using the one supplied with my web and mail servers, where I am reluctant to expose it to the internet at large.

Most weird UAs get a 403 from my system, including accelerators, but the latter don't get a warning message.

I looked into google's accel but I can't afford to screw up my working system and time is in any case in short supply.