This is the Cygwin ftp repository.

Note that, due to excessive download traffic, direct downloads from
sourceware.org (aka cygwin.com) are not allowed.  Attempts to download
will result in a "is marked unretrievable" message.

Please use a mirror if you are interested in downloading anything
cygwin-related.  Refer to http://cygwin.com/mirrors.html for a list
of mirrors.

Or, better yet, use the cygwin setup.exe program to update your
cygwin installation.  You can find it at http://cygwin.com/ .
Click on the "Install Cygwin Now!" link.