Google IP with invalid User-agent

[bull]

As I am always analyzing my raw logs, I noticed the following entry:

216.239.58.136 - - [14/Nov/2005:14:13:03 +0100] "GET /foo/bar/ HTTP/1.0" 200 4362 "-" "Mozilla/4.0 (compatible; MSIE 6.0;)" "212.141.2.*, unknown"

The IP belongs to Google. The IP is used as a proxy: see the HTTP_VIA in the log entry. The User-agent is fake. A external JavaScript file, containing a language switch, was loaded and interepreted.
A member of the german ABAKUS SEO Forum reported similar sightings of this invalid User-agent from a Google IP, three days after mine. This is why I am posting it here.
What is it? A human Google quality rater? Or only someone using Google Accelerator?

sidenote: After some days, traffic on the site (existing since 2001, >1000 pages unique content, more than 6 ODP listings, 2 non-paid Yahoo Directory listings, 2 VLIB listings, misc. college links) visited by the Google IP started to drop to about 50%. Until today.
I do not believe this is a coincidence.

[lammert]

The IP address you mention might be used by Google WAP or CHTML proxy, although most accesses from these proxies on my site are comming from the Google IP 64.233.178.136.

[Xuefer]

maybe it's testing if you're clocking? i'm nore sure if google use ip in the same netmask as crawler

[anttiv]

Could it be related to the Google translation? Do a Google search and you will see traffic logs with this line:

216.239.38.136Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1),gzip(gfe) (via translate.google.com)

Google human raters don't usually fake their UA. They use Firefox ; ) I can give you the ip addresses for both USA and UK if you want.

And while we're talking about IP addresses I'd like to know what's going on with 66-194-6-xx.gen.twtelecom.net - a lot of visits to penalized sites with no referrer.

[bull]

I am a little indignant about the resposes. Having enough experience in log analysis to distinguish a cell phone proxy, translate.google.com and Google service related stuff in general from other log entries, this one was posted here, because I was not the only one who had that visit. There is a minor chance that it was only a Google accelerator user. I initially hoped to find others with similar experiences and not half-baked guesses. Sorry for the rant.

[lammert]

Having enough experience in log analysis to distinguish a cell phone proxy, translate.google.com and Google service related stuff in general from other log entries, this one was posted here, because I was not the only one who had that visit.

First of all, I found the IP address you mentioned also in my log files and my answer in msg #2 was based on my analysis of that visit. The visitor surfed my website like a normal user: the time it spent on each page was comparable with the amount of content per page, i.e. larger pages took more time before a jump to the next page. There was also a logical sequence in the fetched pages from general information to more specific. It is highly unlikely that a bot would mimic a human in such a way, so I strongly believe that it was a human.

Secondly the visitor read my Dutch language pages, although English language pages about the same subject were also available. I remember from a thread some time ago that Google only recruted quality raters from English speaking countries so IMHO it is unlikely that it was a Google quality rater.

Third, I have several entries in my logfile from the Google WAP/CHTML proxy at IP 64.233.166.136 and 64.233.178.136 with exactly the UA string you mention: "Mozilla/4.0 (compatible; MSIE 6.0; )". Therefore it was not a guess, that this IP might be used as a secondary IP for the WAP/CHTML proxy, but based on the content of my logfiles.

Fourth, Google has a very strict way of assigning IP addresses. Look at the numbers for the DC's for example. They all end at the same numbers: 104, 99, etc. Therefore--although without scientific proof--the fact that the two IP addresses I know of the WAP proxy end in 136 is an indication that other addresses ending in 136 are also proxies.