diff --git a/profiles/package.mask b/profiles/package.mask
index bef7626b94df5..0db5157209158 100644
--- a/profiles/package.mask
+++ b/profiles/package.mask
@@ -29,6 +29,12 @@
 
 #--- END OF EXAMPLES ---
 
+# Jonas Stein <jstein@gentoo.org> (10 Dec 2017)
+# Site blocks certain IP blocks from downloading files, while the package
+# may not be mirrored. (bug #640508)
+# Masked for removal on 2018-01-12
+app-arch/defluff
+
 # Thomas Beierlein <tomjbe@gentoo.org> (10 Dec 2017)
 # Development stopped, nasty build system.
 # Functionality superseded by media-radio/wsjtx.