The problem you have is platform related and has nothing to do with py-setuptools. E.g. on my 10.5.8 box I had the same. It happens when the respective source is placed first on some https site and none of the http sites have already received a copy. As port relies on /usr/lib/libcurl.dylib which might provide somehow outdated encodings or ciphers (depending on your MacOSX version), not all https connections will work. In our case, the tarball setuptools-21.2.1.tar.gz first was only present under https://files.pythonhosted.org/packages/source/s/setuptools/, but port just was unable to fetch, probably since your libcurl.dylib (in fact the libcurl.4.dylib) was not built with the asn1 encoding. Or since the ca cert bundle in /usr/share/curl/curl-ca-bundle.crt libcurl.dylib (and also /usr/lib/curl) is using is outdated. Under these two circumstances port cannot download from websites using https.
This analysis is correct. The only upstream download location uses https in a way that older systems' libcurl doesn't support, and the MacPorts mirrors have not yet mirrored the file. Mirroring can currently be delayed by as much as 4 days. See #50875.
MacPorts can't rely on a MacPorts-provided curl library existing. (It won't, for example, when you initially install MacPorts, since no ports have been installed yet at that point.) I've long thought that we should bundle a newer copy of libcurl with MacPorts to solve issues like this. I filed #51516 for this.
I found a hack how to update libcurl.4.dylib on my 10.5.8 PPC box. I downloaded new sources from https://curl.haxx.se/download.html and unpacked the tarball (curl version 7.49.0) . I called the configure script with these parameters:
./configure --enable-shared --disable-static --enable-ldap --enable-ldaps --with-ca-bundle=/usr/share/curl/curl-ca-bundle.crt CC=gcc-mp-5 && make
Some switches I used might be a bit redundant here, and gcc-mp-4.5 or thelike might also do (I did not use Xcode's gcc-4.2 as I noticed some version mismatch between the openssl headers and libraries during configure). Note that I decided to directly refer to the system ca cert bundle, as I found in the full error log from previous py27-setuptools upgrade attempts that no ca cert problems had occurred, but just some asn1 related trouble.
So the rest of the story is short, I copied the resulting libcurl.4.dylib (from the lib/.libs folder) to /usr/lib (of course after making a backup copy from the previous system provided library file with the same name).
And voilà, now port automatically could grab the setuptools-21.2.1.tar.gz from https://files.pythonhosted.org/packages/source/s/setuptools/, while at that moment still none of the repositories using http were offering setuptools-21.2.1.tar.gz.
Admittedly, I am not 100% sure if my hack has no side effect at all, e.g. I hope there was no runtime dependency introduced between the MacPorts installation and the modified libcurl.4.dylib. At the moment I expect that similar https related trouble which has recently occurred with a number of other ports now no longer comes back on my box. As I also have a 10.6.8 box I btw. can tell that there was not such trouble as probably the system provided curl is newer or is just more complete.
Please do not replace parts of OS X in this manner. We cannot support such custom configurations.
