Using DD-WRT on an Asus RT-N16 router to share a 3 MIFI Internet connection on LAN
Yes a snappy title! I’ve spent so long getting this configuration to work that I have to save the info here for my own future reference.
I originally tried to use the latest firmwares and spent a couple of frustrating day’s trying to get it working. I eventually gave up and tried the specifically mentioned firmware below and it worked as expected.
DD-WRT is an open source firmware that can be installed on many different routers. It opens a whole world of possibilities and configuration options, turning a mediocre router in to something that could cost a lot more.
ASUS RT-N16 is a wireless router that is considered particularly good to use with DD-WRT, mainly because it has masses of internal memory which allows you to install the biggest versions of DD-WRT which gives you all the bells and whistles such as OpenVPN, USB support, Hotspot etc.
MIFI is a small portable Internet connected Access Point that connects via 3G/4G. Mine is provided by the 3 network and I can get better speeds using the MIFI than i can from my home ADSL connection. I use the MIFI as a backup internet connection or for when I’m away from home. I wanted a way to share that MIFI connection with my home wired LAN, and DD-WRT is the way to do it.
Here are the instructions that worked for me, they are taken directly from this page
To get the ASUS RT-N16 ready, first visit this page and perform the steps within it: http://dd-wrt.ca/wiki/index.php/Asus_RT-N16 . I first loaded the “dd-wrt.v24-14929_NEWD-2_K2.6_mini_RT-N16.trx” file. After that was flashed, I loaded the “dd-wrt.v24-16994_NEWD-2_K2.6_mega.bin” file. After that, I setup the repeater mode following these instructions: http://www.dd-wrt.com/wiki/index.php/Repeater
I left my MiFi at 192.168.1.1. You should be hard-wired to the DD-WRT router for all these steps and NOT connected to the MiFi. In the DD-WRT router webpage (defaults to 192.168.1.1 in your web browser):
Under Wireless -> Basic Settings:
- Wireless mode: Repeater
- Wireless Network mode: G-only (since the MiFi only does G and not N like my router is capable of, this HAS to match!)
- Wireless Network Name (SSID): the exact SSID of your Verizon MiFi.
- Click the Save button.
- Add a new virtual interface
- Enter a new (unique) SSID of your choice. I used the MiFi SSID with the extension “_VAP” tacked on, but you can use anything. This is the wireless connection you will connect your devices to so that they can all see the wired connections too.
- Click the Save button.
Under Wireless -> Security
- Add the security information needed to connect to your MIFI device.
Under Setup -> Basic Setup:
- WAN Connection Type group:
- Connection Type: Automatic Configuration – DHCP
- STP: Disable
- WAN Port group:
- I checked the “Assign WAN port to switch” to give me an extra wired connection.
- Network Setup group:
- Local IP address: Set to a different subnet from the Host AP you wish to repeat. I used 192.168.2.1.
- Subnet Mask: 255.255.255.0
- Gateway: 0.0.0.0
- Local DNS: 0.0.0.0
- Network Address Server Settings (DHCP) group:
- DHCP Type: DHCP Server
- DHCP Server: Enable
- Start IP Address: 192.168.2.100
- Click the Save button
Under Security tab:
- Uncheck all items in the “Block WAN Request” section (except Filter Multicast)….THEN disable the SPI firewall
- Click the Save button
Under Administration tab:
- Go to the Backup tab and click the “Backup” button to save all your settings to a file.
Finally, go back to the “Setup” tab and click the “Apply Settings” button to get everything to take effect. You may have to turn off the router and MiFi, turn on the MiFi and wait a minute for it to get setup, and then boot the DD-WRT router.
For verification, within a couple of minutes, you can log into the DD-WRT router and on the upper right of the webpage, see something like this: “WAN IP: 192.168.1.x” indicating that your router has successfully connected to the MiFi, and the MiFi has given it an address.
On the MiFI router webpage on the “LAN” tab, you should see that same address listed in the “Connected Devices” section. The MAC address listed here will match the MAC address of your DD-WRT router (which can be compared to in the Status->Wireless tab in the Wireless status->MAC Address of the DD-WRT router.
So, now that the router is all setup I have used it to replace my normal AP which meant changing the SSID to match the old AP and copying all the MAC addresses across to the MAC restriction table. Then it was a straight swap.
I keep my MIFI turned off most of the time, but within a minute or so of turning it on my new AP/router connects to it. Then if I want to use the MIFI as my link to the Internet I only need to change my PC/phone/tablet Default Gateway IP to match the AP and it will route all non-local traffic out via the MIFI.
If my ADSL goes down all I have to do is make a small change on my DHCP server configuration, restart the service and then run IPCONFIG /renew on all my windows machines to pick up the new gateway address via DHCP.
Lovely.
on 20 September 2013 at 11:33
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Hiya, this sounds great, is there any way to make the switching process even easier?
I have a very similar setup, i.e. Asus RT AC66U and a 3 Mifi to use as a backup, can I configure things so that if the normal Internet the Asus is wired to goes down, I can just turn on the Mifi and the Asus will pick it up?
I have a small clinic and I want to set this up for staff who are non technical so even if making a small change to DHCP, restart and run IPCONFIG / renew is ok for me, it would be too much for my nurses.
Is what I am looking for possible?
Thank you for the terrific article
on 30 December 2013 at 0:12
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Hi Daniele,
I’m not aware of any way to make it slicker using DD-WRT, though it may be possible with later versions.
One other possibility might be to look in to pfsense – I’ve recently installed it as a replacement firewall and I’m very impressed with its capabilities. One of which is the ability to load balance or switch between Internet gateways. I’ve not had the time to look in to it yet, but in theory it should be possible to use that feature in some way to route the Internet traffic via the mifi if the main link goes down. Though I have to warn you the learning curve might be a little steep if you’re not used to firewalls and routing etc. If I ever get around to configuring it I’ll probably post the details on this site.
Simon.
on 4 December 2013 at 22:50
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This is a great lil how-to, twas exactly what I was searching for and needless to say will benefit countless others.
Thanks much for sharing how you got it to work and halting my own venture to discovering how to do so.
I will share my own experience with you too some day if God gives the chance.
on 30 December 2013 at 0:14
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Hi,
I’m glad you found it useful, though i can’t take the credit for figuring it all out. I spent days trying to get it working before I stumbled upon the key detail of using a specific version of the firmware.