diff --git a/sources/tech/20161201 How to Build an Email Server on Ubuntu Linux.md b/sources/tech/20161201 How to Build an Email Server on Ubuntu Linux.md
index c13aa00fb5..075b6d54b9 100644
--- a/sources/tech/20161201 How to Build an Email Server on Ubuntu Linux.md	
+++ b/sources/tech/20161201 How to Build an Email Server on Ubuntu Linux.md	
@@ -1,3 +1,5 @@
+translating by dongdongmian
+
 How to Build an Email Server on Ubuntu Linux
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