diff --git a/build-aux/download.scm b/build-aux/download.scm
index 8dfa91460..5cb2491dc 100644
--- a/build-aux/download.scm
+++ b/build-aux/download.scm
@@ -31,7 +31,7 @@
              (guix hash))
 
 (define %url-base
-  "http://alpha.gnu.org/gnu/guix/bootstrap"
+  "http://alpha.gnu.org:80/gnu/guix/bootstrap"
 
   ;; Alternately:
   ;;"http://www.fdn.fr/~lcourtes/software/guix/packages"