Add putty to reusing connections page.

content/connecting/reusing_ssh_connections_in_linux_or_mac.md

 +++
-title = "Reusing SSH connections in Linux/Mac"
+title = "Reusing SSH connections"
 description = "Reusing connections makes it easier to use multiple terminals"
 weight = "37"
 +++
 
+To reduce the number of times it is necessary to enter your credentials,
+it's possible to reuse a single SSH connection for multiple terminal instances.
+
+## Mac/Linux
+
 To make it more convenient for users who use multiple terminal sessions
 simultaneously, SSH can reuse an existing connection if connecting from
 Linux or Mac.  After the initial login, subsequent terminals can use
@@ -28,3 +33,21 @@ file and set the permissions appropriately first:
 
 This will enable connection reuse when connecting to any host via SSH or
 SCP.  
+
+## Windows (PuTTY)
+
+To enable connection reuse in PuTTY, enable the "Share SSH connections if possible" option under
+the "SSH" configuration section.
+
+First, select the saved PuTTY config for the cluster and click "Load".
+
+{{< figure src="/images/putty_share_connection1.png" height="450" >}}
+
+Next, select the "SSH" configuration category. Then check the "Share SSH connections if possible" checkbox.
+
+{{< figure src="/images/putty_share_connection2.png" height="450" >}}
+
+Return to the sessions screen by selecting "Session" at the top and click "Save" to save the settings 
+for future sessions.
+
+{{< figure src="/images/putty_share_connection3.png" height="450" >}}