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--- router_to_router_ssh [2021/09/22 01:36] – [Example] hogwild
+++ router_to_router_ssh [2023/05/23 18:06] – [Overview] -added subhead "Setting up/Eablishing a tunnel" hogwild
@@ Line 1: / Line 1: @@
-====== Enable “Password-less” Router-to-Router SSH Encryption ======
+====== Enable Password-less Router-to-Router SSH Encryption ======
 ===== Overview =====
-FreshTomato includes [[https://matt.ucc.asn.au/dropbear/dropbear.html|Dropbear]], an SSH client/server program. Dropbear can generate a KeyPair that offers password-less connections. A command is run on the primary router which generates a public key.  That Public Key must then be pasted into the secondary router’s //Authorized Keys //field, in the SSH Daemon section of the Administration/[[:admin_access|Admin Access]] menu.\\ This allows command-line management of the secondary router (or "SSH Host") from a primary router, (the "SSH Client"). This can be useful when the system clock is not maintained in the secondary router and time-sensitive jobs must be scheduled. For example, as seen below, it may be useful to switch wireless radio(s) on or off to a schedule (not shown). It could also be used to run scripts on the target for any supported command.
+This setup allows a primary router, (the "SSH Client") to control a secondary router (the "SSH Host"), from the command-line, through an encrypted (tunnel) connection.
+FreshTomato includes [[https://matt.ucc.asn.au/dropbear/dropbear.html|Dropbear]], an SSH client/server program. Dropbear can generate an encryption KeyPair that offers passwordless connections. A command is run on the primary router which generates a public key.  That Public Key must then be entered into the secondary router’s //Authorized Keys //field, in the SSH Daemon section of the [[:admin_access|Admin Access]] menu.\\  \\ This can be useful, for example:
-===== HOWTO =====
+  * When the the secondary router system doesn't maintain a system clock, and time-sensitive jobs must be scheduled.
+  * For running scripts on the secondary router using any supported commands.
+  * As seen below, for switching wireless radio(s) on or off on a schedule (not shown).
-  - On the primary router (the one issuing SSH commands) type the command: \\ **dropbearkey -t rsa -f ~/.ssh/id_dropbear** command to generate the KeyPair. \\ This will display a result similar to that shown below. Leave this window open. \\ You will need it for step 2.
+=====  Setting up/Establishing a Tunnel =====
-\\ {{:pasted:20210921-152323.png}}
+Follow these steps to generate a Keypair and establish an SSH tunnel:
-\\  \\
+  - On the primary router (the one issuing SSH commands) generate a Keypair by typing the command: \\ "dropbearkey -t rsa -f ~/.ssh/id_dropbear" \\ \\ This will display a result similar to that shown below. Leave this window open, as you'll need it for step 2. \\ \\ {{:pasted:20210921-152323.png?744}} \\ \\
+  - Copy the Public key portion from the primary router and paste it into the “Authorized Keys” field in secondary router: \\ \\ {{:pasted:20210921-152415.png?739}} \\ \\
+  - In the above screenshot, a pre-existing, unrelated key was redacted. \\ \\
+  - Now, connect to the secondary router via an SSH session (running on the primary router).  \\ The example below uses the //nvram// command to display the hostname. \\ The first command string ("ssh root@192.168.10.1 nvram get lan_hostname")** **executes the command on the secondary router and then it [nvram get lan_hostname] is executed locally, on the primary router. \\ \\ \\ {{:pasted:20210921-152503.png?741}}
-  - Copy and paste the Public key portion from the primary router \\ to the secondary router’s “Authorized Keys” field, as seen below:
+ \\
-\\ {{:pasted:20210921-152415.png}}
+ \\
-Note that a pre-existing, and unrelated key is redacted above.  \\
-\\
-\\
-  - Now, connect to the secondary router from within an SSH session (running on the primary router). The example below uses the **nvram** command to display the host name. The first command string (**ssh root@192.168.10.1 nvram get lan_hostname) **executes the command on the secondary router and then it [nvram get lan_hostname] is executed locally, on the primary router.
-\\ {{:pasted:20210921-152503.png}}
+===== Usage Example =====
+This example will enable/disable the eth1 5Ghz WiFi interface on the secondary router. (Temperature is shown only when the interface is enabled).  \\  \\
-==== Example ====
+  - This screenshot shows the status display of the Primary router before before the command is run: \\ \\ {{:pasted:20210921-152542.png?736}} \\ \\
+  - Now, we run the command (//ssh root@192.168.10.1 radio toggle 1//): \\ \\ {{:pasted:20210921-152607.png?744}} \\ \\
+  - This shows the status display after the command is run: \\ \\ {{:pasted:20210921-152637.png?761}} \\  \\ Since "radio toggle 1" is  a toggle switch, if the same command is repeated, the eth1 interface will be disabled on the primary router.
-This example will enable/disable the eth1 5Ghz Wi-Fi interface on the secondary router. (Note that temperature is shown only when the radio is On).
 \\
-\\
-  - This shows the status display before ([Primary router) the command is run.\\ {{:pasted:20210921-152542.png}}
-\\
-  - Command [**ssh root@192.168.10.1 radio toggle 1**] executed.\\ {{:pasted:20210921-152607.png}}
-\\
- - Here is the status displayed after the command is run.
-\\ {{:pasted:20210921-152637.png}}
+ \\
-\\
-\\
-(If the same command is repeated, eth1 will be disabled on the primary router.)
-\\ **Notes**
+===== Notes =====
-\\ SSH must be enabled on both routers. \\ The key generated is not preserved across a reboot of the [primary] router. Either keep a copy of the id_dropbear file offline [on a UFD or “CIFS Client” share] for restoration, or be prepared to repeat the procedure [steps 1 & 2 under “**How To**”] after a reboot [removing any redundant key from the secondary router during the process]. \\ This guide was produced using [[https://www.chiark.greenend.org.uk/~sgtatham/putty/|PuTTY]] [v0.76] and FreshTomato v2021.5. \\ Insiration was provided by [[https://blog.michael.franzl.name/2017/09/03/set-passwordless-ssh-login-dropbear-client/|this]] article [and this process was first documented [[https://www.linksysinfo.org/index.php?threads/%E2%80%9Cpassword-less%E2%80%9D-router-to-router-ssh-how-to.76761/|here]]].
+  * The SSH daemon must be enabled on both routers.
+  * The key generated will be erased after a reboot of the Primary router.
+    * Either keep a copy of the "id_dropbear" file offline (on a flash drive, or CIFS Client share) for restoration, or;
+    * Be prepared to repeat (steps 1. and 2.) after a reboot, removing any redundant key from the secondary router.
+  * This guide was produced using [[https://www.chiark.greenend.org.uk/~sgtatham/putty/|PuTTY]] v0.76 and FreshTomato release 2021.5.
+  * Inspiration was provided by [[https://blog.michael.franzl.name/2017/09/03/set-passwordless-ssh-login-dropbear-client/|this]] article.
+  * The process was first documented [[https://www.linksysinfo.org/index.php?threads/%E2%80%9Cpassword-less%E2%80%9D-router-to-router-ssh-how-to.76761/|here]].

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