Comment 8 for bug 252840

I can confirm this problem(but example are not enough,changing to new.).

I'm administrator of ubuntu mirror server 'ubuntu-ashisuto.ubuntulinux.jp'.
It is registered at https://launchpad.net/ubuntu/+mirror/ubuntu-ashisuto.ubuntulinux.jp

I recieved automated failure notice from Launchpad that from below probers error at 2008-08-21
http://launchpadlibrarian.net/16964954/ubuntu-ashisuto.ubuntulinux.jp-probe-logfile.txt

But mirror server is fine, and *does not* logging any probers behavior.
So, mirror checker output 503 respond without any access. It looks like the proxy/http-client error.

In good case, mirror-prober that from 91.189.90.174(druzhnaya.canonical.com)., comming with HTTP: "HEAD /ubuntu//dists/<release-name>/<repo-type>/binary-<arch>/Packages.gz HTTP/1.0".
our mirror server logged below.
91.189.90.174 - - [08/May/2008:09:17:31 +0900] "HEAD /ubuntu//dists/intrepid/restricted/binary-i386/Packages.gz HTTP/1.0" 200 - "-" "-"

But, adove "Bad response code: 503" are not logging by ubuntu-ashisuto.ubuntulinux.jp.
I cannot found any other probers' log from httpd's logfiles(includinig errorlog file).

May be mirror-prober does not come at 2008-08-21..., but it logged bogus 503 error. (Of cource, I calculated the time difference of UTC=>JST)

Please check....