Addendum: This only happens on ipv4, ipv6 on 2001:7a8:363c:2::2 is fine:
bkw@Aeronaut:~$ curl -6 -I -H "Host: haproxy.org:80" http://haproxy.org/download/1.5/src/haproxy-1.5.0.tar.gz HTTP/1.1 200 OK Date: Mon, 23 Jun 2014 12:38:00 GMT Last-Modified: Thu, 19 Jun 2014 19:06:22 GMT Accept-Ranges: bytes Content-Length: 1329040 Cache-Control: max-age=28800 Expires: Mon, 23 Jun 2014 20:38:00 GMT Content-Type: application/x-gzip Server: Apache (Unix; Formilux/0.1.8) On 23.06.2014, at 14:08, Bernhard Weißhuhn <[email protected]> wrote: > Hi, > > I noticed a strange behavior on the haproxy.org servers, which unfortunately > is being triggered trying to download the source from a chef-client. > > When downloading the tar.gz, the chef client sends ":80" as part of the host > header (which is legal from my understanding of the rfc). > This header reliably results in a 404, whereas leaving out the port number > results in a successful download: > > [...]

