I wasn't sure if some/many/all Debian mirrors responded correctly to HTTP/1.1 range requests for only part of a file, so I ran a test on them (download part of the etch Release file). These type of requests will be useful for downloading missing pieces from packages in the BitTorrent-like downloader that I'm writing.

Here are the results of my test on the 221 HTTP mirrors:

Status Description Count
200 Full Data 1
206 Partial Data 208
302 Document has moved 2
404 Not Found 2
Couldn't Connect 8
Total 221

So only one mirror (debian.csie.nctu.edu.tw) was unable to support the range request and instead returned the entire file. It seems like using range requests will be fine, though I'll have to think about some kind of error checking for that one lonely mirror that's not like the others.

There was also one mirror that responded with an old Release file. It seems like debian.ihug.co.nz has not been updated since etch was released.