Msg#: 4497999 posted 1:02 am on Sep 21, 2012 (gmt 0)
Ted told me I should be able to search for this topic discussed here recently. Unfortunately I can find nothing at all.
I received an email from Google with the subject "Googlebot can't access your site http://example.com/".
Which of course is rubbish. I rarely look at webmaster Tools but for quite some time now Google has had my site under two names.
http://www.example.com/ [correct] and;
http://example.com/ [incorrect] and the thrust of the email from them.
Over the last 24 hours, Googlebot encountered 1 errors while attempting to connect to your site http://example.com/. Your site's overall connection failure rate is 50.0%. You can see more details about these errors in Webmaster Tools
Msg#: 4497999 posted 8:05 am on Sep 24, 2012 (gmt 0)
The server would have to perform some equivalent of the -d and -f test on every request, and pore over your htaccess to make sure the request isn't coming from someone who will end up being blocked (core comes after all mods including rewrite). You're looking at a significant detour into a php script for every single request, because a server-level redirect on its own would happen before the request ever reaches your individual site.
someone has to do the work eventually. the best solution is to host both virtual hostnames on the same server so you can do this work for the first request instead of delaying it until the subsequent request.
I just wanted to chime in here and say that I have been seeing the same things. We get constant errors in GWT like the ones described above. Even weirder, we are getting requests for strange robots.txts.