Debugging shows loads of requests to Bing?

[Chuz]

I recently had the need to set up my Galaxy S5 to use my laptop as a proxy, in order to inspect web traffic in Fiddler.
Incidentally, amongst all the http requests I expected to see, I'm noticing that my phone will periodically make a lot of requests to ht tp://204.79.197.200/, which is owned by Bing.com.
Nothing is being sent so I have no concerns on that front, but I cannot think of any apps I have with any need for that site. The only app with any affiliation to it would be the Remote Desktop app I use (developed by Microsoft).
This has been going on for weeks, although admittedly I haven't cared quite enough to take note of how frequently this occurs (I will do so now and update), nor have I started selectively uninstalling apps to try to identify the culprit.
Or is this normal? Is this a network test by the Android OS or something?

Here is what happens:

Request to ht tp://131.253.13.140/
Location header in response specifies "Location: ht tp://www.bing.com/".
It doesn't seem to follow this though, or maybe it tries to be clever and thinks it already knows the IP for that, because then over the next 2-3 minutes it sends 1,500 requests to:
ht tp://204.79.197.200/
Yes, that's one thousand, five hundred requests.
Again, the Location header in each of these responses is always "Location: ht tp://www.bing.com/"
It's like it gets stuck in a redirect loop and goes mental for a few minutes, not knowing when to stop.
And then, when it is seemingly exhausted, it heads over to Google (eg. ht tp://74.125.237.212/ or ht tp://74.125.237.210/) and stops. This is what makes me think that it's some kind of network status check; it's as if it just wants to load a website, any website, to confirm that it can.


(note: spaces added to urls as new members cannot post links)

 

[Chuz]

And it just happened twice more, occuring 2 minutes apart.
Again it was a request to ht tp://131.253.13.140/, and this time about 600 requests to ht tp://204.79.197.200/ and then finally ended when it went to a Google IP ht tp://74.125.237.209/.
About 1 minute and 40 seconds later, off we go again. ht tp://131.253.13.140/ followed by about 800 requests over 7 minutes to ht tp://204.79.197.200/ and ending up on ht tp://74.125.237.211/.

And by the time I finished writing that, less than a minute later it did the same but this time with only 7 requests.

This is bizarre... I had no idea until now that it's so frequent.

 

[Chuz]

Ok I made some progress figuring this out.

It is a network status check. I can now invoke it any time by turning mobile data off and back on. I believe this makes it check all network connections, presumably so that it can see if wifi is connected and preferentially use that over the mobile network.
It seems to have a few pre-defined IPs to use for this purpose. When I turn mobile data on, it randomly says hello to one of Yahoo, Amazon, Google or Bing. The last of these is the one that sends my phone on a wild goose chase with never-ending redirects (not that the site is to blame, it seems Android doesn't properly follow the instructions).
So approximately 1/4 times (or rather 1/4 times for EACH connection, as I'm guessing it does the same using mobile data as well, but I can't see these), it sends a mountain of requests to keep retrying Bing. Eventually it gives up and decides to use a Google IP instead, which succeeds and the phone is now satisfied that it has a connection (and assumes the fault to be with Bing).

So, apologies for the thread, seems I found the cause of it. I'm guessing it must sometimes grab a new set of IP addresses from Google so hopefully that happens soon and it can clear out this mess, or an Android update can make it properly handle a response of that nature. Unless this is a weird anomaly in my network (I doubt it), this is probably happening to everyone whose phone is told to check Bing. Interesting and annoying, more than harmful.