RFD: Please add ports.ubuntu.com to ubuntu mirrors

copied over from https://bugs.launchpad.net/ubuntu/+source/apt-cacher-ng/+bug/227733/comments/14:

Can we also get http://ports.ubuntu.com listed as ubuntu mirror? On systems which use official arch as host + ports arch for tools like xdeb (Cross compilation stuff) APT often tries to fetch arch=all packages from ports which is much slower for most of people.

-- hrw

Copying Eduard's response from https://bugs.launchpad.net/ubuntu/+source/apt-cacher-ng/+bug/227733/comments/18:

Ok, I see. I am not sure whether this can be achieved without collateral damage. That means, the idea of mirrors in a mirrors list is to refer to mirrors with identical contents. Handling partial mirrors is complicated because apt has different interpretations of a "404 Not Found" response.

I added an experimental feature once (read: an evil hack) to do such things trying to identify the client ID by connection and judging by the files that it wants to retrieve (search for "keyfile" in the manual). You might try that and report the results, but I cannot promise anything.