diff --git a/ChangeLog b/ChangeLog
index 28c9c706d5..2d26904f0b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Dec 14 23:53:41 2017  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* test/net/ftp/test_ftp.rb (process_port_or_eprt): merge a part of
+	  r56973 to pass the test introduced at previous commit.
+
 Thu Dec 14 22:55:05 2017  Shugo Maeda  <shugo@ruby-lang.org>
 
 	Fix a command injection vulnerability in Net::FTP.
diff --git a/test/net/ftp/test_ftp.rb b/test/net/ftp/test_ftp.rb
index ae07a59056..fbb3bf246e 100644
--- a/test/net/ftp/test_ftp.rb
+++ b/test/net/ftp/test_ftp.rb
@@ -1900,4 +1900,22 @@ EOF
       end
     end
   end
+
+  def process_port_or_eprt(sock, line)
+    case line
+    when /\APORT (.*)/
+      port_args = $1.split(/,/)
+      host = port_args[0, 4].join(".")
+      port = port_args[4, 2].map(&:to_i).inject {|x, y| (x << 8) + y}
+      sock.print("200 PORT command successful.\r\n")
+      return host, port
+    when /\AEPRT \|2\|(.*?)\|(.*?)\|/
+      host = $1
+      port = $2.to_i
+      sock.print("200 EPRT command successful.\r\n")
+      return host, port
+    else
+      flunk "PORT or EPRT expected"
+    end
+  end
 end