Lance,

Let's go at this from another angle.

I am absolutely certain having analysed the logs that the excess bandwidth was caused by people downloading .iso images for centos from our master mirror(s) ....

How could this happen?

Here is my explanation:

1) As far as I am aware, the cAos site does NOT ask distro users to download from public mirrors, rather than from the master mirror.

2) On install, yum.conf points to the master mirror.

3) Even if a distro user puts in a custom yum.conf file that points to a public mirror, "yum update" can remove the custom yum.conf file, and put in its place a yum.conf that points to the master mirror.

4) From 2 & 3, I got the impression that it is OK, even encouraged, to download directly from the master mirror. This is supported by the lack of any request not to do so, 1.

5) Maybe lots of other distro users got the same impression as 4.

That is my explanation.

Does anyone have a better explanation for Lance's analysis of the logs?

Rick