WARNING: This is information on how to root your modem. Rooting is to take full control, like rooting your Android phone. It WILL void your warranty, It can possibly brick your modem. USE AT YOUR OWN RISK
If you're just wanting to fix the annoying "potential connection issue" redirect problem, some kind soul has made an awesome Youtube Video referencing this page.
I have finally found a vulnerability in the NVG510's WebUI! What does this mean? You can now get a root shell without doing any soldering on your modem.
Here is how to do it. (I already had this written, but the stupid lan-redirect issue bit me and made me lose my post, so I apologize if it's a bit short on details)
- View the ethernet configuration page, which should be at http://192.168.1.254/cgi-bin/etherlan.ha
- Login if you haven't already.
- Now you'll want to view the HTML source of the page.
Search for the term "nonce" in the HTML source. You should see something like this:
Hang on to that piece of text and now load my complete_control page.
- Take the "value" of the nonce and put it into the text field labeled nonce on the page.
815a0aaa0000176012db85d7d7cac9b31e749a44b6551d02would be what you put into it for this example.
- Load the page up and push Save.
- You should now see the ethernet configuration page and
Changes saved. If you instead get redirected to the home page, try copying the nonce value again.
- Now you should be able to login to the modem with telnet. The username is
adminand the password is your modem's "access code" that should be written on it.
- Finally, you should see the shell. This isn't a very good shell though. To break out of it and get to a real root shell, just enter
!. To clarify, your telnet session should look like this:
[earlz@EarlzZeta ~]$ telnet 192.168.1.254 Trying 192.168.1.254... Connected to 192.168.1.254. Escape character is '^]'. login: admin Password: Terminal shell v1.0 Copyright (C) 2011 Motorola, Inc. All rights reserved. Motorola Netopia Model NVG510 Wireless-N ADSL AnnexA Ethernet Switch Running Netopia SOC OS version 9.0.6 (build h0d48) ADSL capable (admin completed login: Admin account with read/write access.) NOS/XXX> magic Warning: Accessing these commands is restricted, and will affect normal operation of this device. Exit now if you entered by mistake. NOS/XXX/DEBUG/MAGIC> ! #
After you get to the root shell you can do whatever you want!
Note: Use this information at your own risk. From the root shell, you can brick your modem so be careful!
Solving common problems
Once you get to the root (
#) shell, type in
nsh and press enter. Then, you can try some of these common problem fixes. To confirm you're at
nsh, you should see a prompt like this:
The nsh Console
This console is actually fairly simple and easy to use, and breaks out everything that you can configure on the modem. But, it is not the console described in the FCC manual.
This is the help text for the console, to help you understand:
Axis/124578433> help help [command] : Get help. history : Show command history. get OBJ.ITEM : Get the value of OBJ.ITEM (ITEM is a parameter or status). ### Hint: run 'info OBJ.params' or 'info OBJ.status' to get a list of the OBJ's parameters and status. set OBJ.ITEM VALUE : Set the value of OBJ.ITEM to VALUE. info INFO [ARGS ...] : Get the INFO information (expert mode). new OBJ [NAME] : Create an object with an (optional) name (requires an 'apply') del OBJ : Delete an object (requires an 'apply') aget OBJ.ITEM ATTR : Get the OBJ.ITEM's ATTR attribute. aset OBJ.ITEM ATTR VALUE : Set the OBJ.ITEM's ATTR attribute to VALUE. name OBJ [NAME] : Get or set the OBJ's "name" (specify a new name to set it). names [OBJ] : Recursively show all object names. validate [OBJ] : Validate OBJ, or the entire database if no OBJ specified. apply : Apply changes to the database (changes are NOT saved). revert : Revert the database by discarding your changes. save : Save the database (rewrites config.xml). defaults : Reset the system back to the factory defaults (deletes config.xml). dump [OBJ [LEVELS]] : Dumps the OBJ's parameters, or the entire database. Use the optional LEVELS parameter to limit the depth of the database tree. sdump [OBJ [LEVELS]] : Dumps the OBJ's status, or the entire database. tdump [TEMPLATE [LEVELS]] : Dumps the template, or the entire SDB schema. dirty [OBJ] : Displays which parameters are dirty. run CMD [ARGS ...] : Run the SDB's CMD command (expert mode only!). event EVT [ARGS ...] : Send the EVT (event number) to the SDB (expert mode only!). console [on | off] : Direct all log messages to this console. Without arguments, toggles on and off. log [OPTIONS] : View log messages. See "log help" for more information. voiplog [OPTIONS] : View log messages. See "log help" for more information. mfg [OPTIONS] : Set or view MFG parameters. See "mfg help" for more information. mirror [PORT CAPTURE-PORT] | "off" : Mirror Ethernet traffic on PORT so that it may seen on CAPTURE-PORT. Specify "off" to turn mirroring off. resetstats [OBJ] ["all"] : Reset any statistics the object may have. The optional "all" argument will recursively reset all children's stats as well. If only "all" is given (OBJ is omitted), this will reset all statistics starting at the root node. metadata OBJ.PARAM : Returns metadata information about a given parameter. fwinstall URL | "last" : Install a firmware image. Use "last" to reuse the last URL. crashdump ["erase"] : Shows the most recent crash dump contents. The optional "erase" will erase both current and last saved crash dump contents. reboot [N] | ["cancel"] : Reboot the router in N seconds (default is 2). "cancel" argument can be issued to cancel a previous reboot command. source FILE : Read and process commands from FILE. . FILE : An alias for 'source'. exit : Exit from this shell. quit : An alias for 'exit'. magic : Enter magic mode. crash : Read and Write the Memory mapped registers
Well, seems simple enough then doesn't it?
So, let's say you want to enable SSH. The relevant configuration option for this is
mgmt.shell.ssh-port. So, to set this, we type this in:
set mgmt.shell.ssh-port 22
This will set the SSH port to 22, rather than disabled. And then, if you're done configuring, you can save and apply the changes by typing these commands in:
validate apply save
You don't necessarily have to do validate, but I assume it's safer to use it I think. I believe that this is what happens:
validatewill validate the changes to make sure that no data was input in a way that wouldn't make sense (like if nameserver was set to
applywill actually cause the modem to notice the changes and begin executing using those changes you've made
savewill cause the changes you made to persist after reboot. I assume it saves it to flash with this command.
That's really about all there is to know. Configuration is super simple.
As you can tell from the dump log, there are a ton of configuration options. Here I'll give you a hint to the more useful ones, as well as some configuration stuff to be aware of
DNS problem fix
This is provided for historical reasons, but it's WRONG. This will not fix the DNS problems or let you point it at a different DNS server. I don't know why it doesn't work, but I've received multiple reports that it doesn't. Your best bet in this case is to use the true bridge mode and get your own router
ip.dns.domain-name = att.net ip.dns.primary-address = 126.96.36.199 ip.dns.secondary-address = 188.8.131.52 ip.dns.proxy-enable = on ip.dns.override-allowed = off
You should be able to change these to something more appropriate.
override-allowed should be turned on(otherwise I believe they will be reset by DHCP over the DSL link).
Enabling Telnet and/or SSH
mgmt.shell.ssh-port = 0 mgmt.shell.telnet-port = 0
These you should change to what port you want it to run on. Note though that I've yet to figure out the username and password used for SSH. I've searched through both the dump and through the GPL source code and can't find any hints really.
So, to enable these you can just do something like
set mgmt.shell.ssh-port 22 set mgmt.shell.telnet-port 23 validate apply save
If you want to enable remote access to telnet and/or ssh (I highly recommend not opening up telnet to the world) you can modify these values to something appropriate:
mgmt.remoteaccess.protocol = telnet mgmt.remoteaccess.port = 0 XX change this to 23 mgmt.remoteaccess.idle-timeout = 5 mgmt.remoteaccess.total-timeout = 20 mgmt.remoteaccess.max-clients = 4 mgmt.remoteaccess.protocol = ssh mgmt.remoteaccess.port = 0 XX change this to 22 mgmt.remoteaccess.idle-timeout = 5 mgmt.remoteaccess.total-timeout = 20 mgmt.remoteaccess.max-clients = 4
I haven't confirmed this, but I believe UPnP can be enabled by changing this to on:
mgmt.upnp.enable = off
Disable "Potential Connection Issue" warnings
mgmt.lan-redirect.enable = on
Change it to
off. lan-redirect is what causes that extremely annoying redirecting to happen when the connection is lost or "has possible problems". What the modem will do is when you request a nameserver, it will, instead of sending back no route, timeout, or the actual name servers response,
it will instead make every domain forward to 192.168.1.254, so that you can then load an HTML page that causes a redirect(but doesn't set it to do-not-cache) to
/cgi-bin/home.ha... So basically, you click
do not show, yet the page continues to try to redirect
due to modern web browser caching and the lack of a no-cache directive on the redirect page.
Disabling the DHCP server
conn.dhcps-enable = on
Note that you'll have to configure a static IP to the modem to access it after this. I don't see much of a point in disabling it completely.
Other Dangerous Things
From this bootloader, you can change a lot of things AT&T probably would frown upon. Basically, you can make it look like another modem. I'm not for sure about this though and will have to test it and research it more. I don't recommend changing anything in the
mfg section. If you do one of these kind of hacks, be prepared for AT&T to notice and ban you from U-Verse
The NVG510 is really a decent modem, but has been kiddie-proofed so hard that it hurts. I hope this guide helps you to taking full control of your modem. Also, I don't recommend trying to evade your U-Verse accounts capabilities. I imagine AT&T won't care much if they catch you modifying your modem... they will care if you modified it to reach 16Mbit speeds when you only have a 3Mbit account though, and I'm sure they keep tabs on it. Don't be stupid.
Same goes for trying to boost wifi power or use channels not specified for use in your country. The FCC is real! (btw, don't tell them about my FM transmitter project ;) )
True Bridge Mode
A very often wanted feature of the NVG510 is for it to just get out of your way and let your (hopefully more sane) router to deal with all the firewall and NAT business. After quite a bit of experimenting and starting over with
default and a bit of an accident, I believe I've figured it out.
Some of the values in the NVG510's configuration "database" appears to be magical, and lots of assumptions have to be made without real technical documentation. So, let's look at the
link object that appears to be linked to WAN and LAN
connections in an assumed manner.
Here is what was in my modem's dump about
links. Your's should look similar:
link.type = ethernet link.igmp-snooping = off link.mtu-override = 0 link.port-vlan.ports = lan-1 lan-2 lan-3 lan-4 ssid-1 ssid-2 ssid-3 ssid-4 link.port-vlan.priority = 0 link.type = ethernet link.mtu-override = 0 link.supplicant.type = eap-tls link.supplicant.qos-marker = AF1 link.supplicant.priority = 0 link.port-vlan.ports = vc-1 link.port-vlan.priority = 0 link.tagged-vlan.ports = ptm link.tagged-vlan.vid = 0 link.tagged-vlan.priority = 0
ptm is the PPP connection. So we basically want for the PPP connection to be routed straight to an ethernet port so our router can handle it. So here is what I did
set link.port-vlan.ports "lan-2 lan-3 lan-4" set link.port-vlan.ports lan-1
The first command sets the
LAN link so that only the LAN ports 2-4 is used. The next link sets the link for the
WAN side of the link. Previously, the port is vc-1. I assume vc-1 is hardwired to magically go to the
LAN somehow. Anyway, replacing vc-1 with
lan-1 basically makes the equivalent of a PPP bridge.
On the router side, all you have to do is use that port and the modem will do all of the PPP authentication, and I assume MRU shifting to 1500.. All your modem will get is a raw stream from AT&T's servers. So if you send it a DHCP client request, you'll get a response straight from AT&T's servers.
This is the only configuration required as well. This will short through all of the modem's crappy configuration and directly forward it to the first ethernet port(the one closest to the barrel jack power adapter).
And if for some odd reason you need to access the actual modem(such as for reconfiguration), just plug your network cable into another port. The built-in DHCP server runs just as before, except it will never be connected to the internet.
Possible Problem: If your modem seems to "hang" when doing
apply with the bridge mode configuration and you can't use the
save command, then that means you tried to do it from port-1. Change which port on the NVG510 your computer is plugged into(or use Wifi if you're extra brave)
Configuration Template You can dump this for yourself, but to see what Motorola's "template" is for it's configuration options you can check out this pastebin. If you don't know what options a configuration object supports, this is a good bit to look at. Though a few things in the template don't exist in my NVG510 at least and will cause crashes if objects are created. (cifs will not work for me)