Using VPN & DD-WRT with a DSL Modem Router Combo (FlashRouters FAQ)

Our best ideas always start with you, our readers and customers. One recently sent us a question that we receive pretty frequently. So we figured we’d publish the latest in our series of popular FlashRouter FAQs.

Open Source Firmware on DSL Modem Routers

I have a DSL modem from my ISP. Can I flash my DSL modem/router with DD-WRT so I can use VPN on it?

– Chip in Chattanooga, TN

Thanks for the question Chip! The simple answer is no. DD-WRT firmware is not compatible with DSL, VDSL or ADSL modem combinations.

A common issue for many users looking to integrate DD-WRT or Tomato within their setup is the fact that modems and modem routers cannot be flashed with Open Source firmware. As these devices do not use Broadcom or Atheros chips and the drivers for these products have not been made public or released to open source development teams, modem routers simply have not developed with and cannot be flashed with alternative/non-ISP firmware.

There are two major reasons we see this as the case.

1. DSL Modem/Routers Are Usually Outdated, Cheap Throw Ins – Usually DSL modem router combo devices are offered with outdated technology to minimize bandwidth use which cost providers more. So basically, the more powerful the router, the more bandwidth you will use. Therefore, they offer you a free device that gives you just enough to keep you somewhat happy without maximizing the capabilities of your network.

Even the best DSL modem router, being a combination of a modem and a router, is a less powerful device when compared to a standalone router or FlashRouter, as the specs of the device need to be lessened to host an actual modem.

They usually force you to rent this underpowered device which also adds to their profits. Generally, the router part of these modems are basic single band wireless-N devices with a 300-400 MHz processor with max wireless transmission at 300 Mbps with older generation fast Ethernet ports. If you upgrade to a higher plan, they might throw you a bone and double that wireless speed to up to 600 Mbps transmission power with average range.

You will not see a Wireless-AC device with max range for transmitting streaming video signal through you home or 1 GHz processors of up to 2400 Mbps. We are talking a minimum of 3-4 times as powerful devices when it comes to standalone Wireless-AC DD-WRT options.

2. ISPs Want To See Your Traffic Usage & Data – The average customer just wants their router to work so an ISP has limited impetus for improved, enterprise level firmwares.

Open-source firmwares are developed to be used on standalone routers and the modems complicate the firmware part. Plus these modem routers are usually an under-powered combination.

Using VPN with a DSL modem router combo network-wide is not a built-in option that most ISPs do or will ever offer. ISPs are in the business of monitoring and managing traffic so to offer built-in protection for privacy protocols like VPN is antithetical to their business model, meaning it will not make them money.

Using VPN with a DSL Modem Router

The best option for users having this dilemma is to use a VPN FlashRouter in tandem their DSL modem/router combination. Add a DD-WRT or TomatoUSB behind it to router and manage your traffic as your main network gateway using the FlashRouters Dual Router Setup.

Use a FlashRouter in a Two Router Setup - Local & VPN

How To Use a FlashRouter in a Two Router Setup

Within a Dual Router Setup, the modem router maintains a connection to your ISP, passing that connectivity to a DD-WRT or Tomato FlashRouter alongside it, creating a second network more powerful network with limited setup or frustration. If you choose to use your FlashRouter as a VPN (Virtual Private Network) router with a service like IPVanish, your second network will be a VPN-dedicated device network so you can add any devices connected to the network will be encrypted by a VPN.

Most Popular/Best DSL Modem Router Combos By Region

Telmex Technicolor Modem Router

Telmex Technicolor Modem Router

As the world is covered by a diverse list of Internet Service Providers, there are many modem routers that may have found their way into your home, such as the:

  • Telmex, Prodigy (Mexico, Brazil, and the rest of Latin America)
  • Movistar, Jazztel (Spain and Latin America)
  • Orange (UK, France, Kenya, Poland, Switzerland, etc.)
  • Virgin Media, Sky (UK)
  • Foxtel, Telestra, Optus (Australia)
  • FRITZ!Box, Deutsche Telekom (Germany)
  • Etisalat, Oger Telecom (Middle East)
  • Verizon, Comcast, AT&T, Time Warner, Optimum, Spectrum, Cox (United States)
  • KT, CJ HelloVision (Korea)
  • Rogers Cable, Shaw, Telus (Canada)
  • Cablecom, DFI (Switzerland)
  • Sahara Net, Saudi Net (Saudi Arabia)
  • Asahi Net, NTT EAST (Japan)
  • …and any other DSL/Cable/Fiber-Optic modem router from any provider around the world!

A FlashRouter can work alongside any of the these popular ISP’s and their modem/router combinations. The process is as simple as connecting a FlashRouter to a modem router via Ethernet cable. Once this connection is established, you have will have two networks, one for your ISP and one, if you so choose, for your VPN connection.

If you are using a modem router from any provider, we can support it. Want to be sure? Contact our networking specialists and we can look into it and add it to this list for other potential users.

DD-WRT Router To Use VPN with a DSL Modem Router Combo

Asus AC5300 - 8 External Antennas

Asus AC5300 DD-WRT FlashRouter


Whether you are a Telmex customer in Brazil, a FusionGOL subscriber in Japan, or a Comcast user in the United States, a FlashRouter will comfortably slip right into your setup behind a modem router combo. Here’s just a few of our enhanced router favorites FlashRouters ready to overhaul your DSL, ADSL, or VDSL network connection!

  • Netgear R7000 Nighthawk DD-WRT – The R7000 Nighthawk comes complete with a 1 GHz processor and 3 external antenna and is our favorite networking superhero!
  • Asus RT-AC5300 DD-WRT – Our best-ranked and highest performing router is the RT-AC5300 with 8 powerful external antennae. Adding these antennae to this powerhouse 1.4 GHz processor, you will not only receive great range but a powerful performance allowing for high-quality streaming, lag-free gaming, and a strong connection to your VPN provider, be it ExpressVPNIPVanish, or countless other FlashRouters supported VPN providers.
  • Linksys WRT1900ACS/AC V2 DD-WRT – A nice Linksys alternative with high end processing and great WiFi range thanks to its 4 external antennas. A great value!
  • Asus RT-AC56U DD-WRT – If you are looking for a router that is a little less powerful but with comparable specs to the most powerful routers, the AC1200  is a fantastic choice for a mid-range processor, packing a competitive 800 MHz processor that is comparable to routers almost twice its price.If you are interested in a completely wired setup, this is a great choice. While the AC56U lacks external antennae and cannot offer the same wide-reaching wireless range as those that do, in terms of processing power alone, it surely is a high performing VPN ready device.

Need more info? Don’t hesitate to shoot us a message and our team will be more than happy to walk you through the process.

22 thoughts on “Using VPN & DD-WRT with a DSL Modem Router Combo (FlashRouters FAQ)

  1. Ted

    First off, thanks for the info. My situation is that I live in Germany and am currently connected through a modem/router combo (Hitron CVE-30360). I have purchased a Netgear R6000 and plan to make it my openvpn DD-WRT router.

    If I connect my DD-WRT router to my modem/router combo, will it slow down my connection speeds on devices connected to my DD-WRT router? Is there a benefit or difference of this configuration vs setting the modem/router combo on bridge mode and having the DD-WRT router be handling internet connections? On most posts online, I found that users suggest putting the modem/router into bridge mode since the router within the combined unit is not as useful as a standalone router.

    1. joeso

      Hello Ted,

      We have users going both ways on this. It depends if the goal is having a VPN connection and a non-VPN connection, the dual rotuer segment the needs. But if you want just an openvpn connection through the network, bridging is a fine option.

  2. thoughtscape2010Mick

    Hi. I’m really not sure where you get your information from dude but I flashed my ADSL Buffalo WBMR-HP-G300H [which IS a modem router combo] from a completely DD-WRT noob status and it has been working without a hitch. Or were you specifically talking about the modem routers that ISPs give you? In which case I agree. The MP252BW from iPrimus [Australia] sucks the big one and there’s nothing to do but buy a DD-WRT compatitable one .

    Other than that, your page was pretty useful and probably a good place to start for someone just getting into VPNs.

    1. joeso

      Thanks for the compliment on the page.

      We were mentioning ISP modem/router combos. There is a buffalo model but we have had many issues when it comes to Buffalo models and replicating successful VPN setups so at this time we don’t support Buffalo.

  3. Tony

    Please excuse me since qwhile no technophobe I am a bit lost here. I live in France and use an Orange Livebox for telephone, internet and wifi. However, I want to access UK catch-up TV and there is no way I can use a VPN with the livebox to change my IP address. How would a second router help and be configured? Direct from the computer which has the VPN on? And would I then have two wifi signals? Sorry to trouble you, but it is confusing to a bear with little brain.

    1. joeso

      Hello Tony,

      We’re glad to try and clarify.

      The Livebox is not VPN compatible alone but since it is a modem and a router you need it to use Orange’s service. So we offer a second router that can be connected to the livebox and add box wired and wireless VPN connections.

      You can see this in action on What is a Dual Router Setup page.

      If you have any further questions send them to and they would be glad to clarify

  4. Alex

    I cant decide what to buy.. Are u Guys still going for the Netgear R7000 DD-WRT? Cause I read in some Reviews that the Netgear R6400 should be beter in WLAN (real) Performance then the R7000.
    And the R6400 is much never then the R7000.

    Hope u can answer me.

    1. admin

      Hello Alex,

      The R7000 is still our overall best-seller and most popular selection. We do not currently offer the R6400.

      Please let us know if we can assist you any further.

  5. Pingback: Dd-wrt How To Access Dsl Modem | Information

  6. Juan

    You say the cheap ISP DSL modem limits bandwith.

    My question is: if you connect a fast VPN DD-WRT router to the cheap ISP modem, will the cheap ISP modem simply pass along to the VPN router the limited bandwith or will the VPN router be able to take full advantage of the ISP internet bandwith?

    In this case, would it be better to replace the ISP DSL modem with a better DSL modem and then connect the VPN DD-WRT router?

  7. Jerry Bozeman

    Will a Netgear R7000 Nighthawk DD- WRT work with a model C1100T made by technicolor? If it will will it help your wifi power or bandwidth. Finally what is the best way to set it up to get the most out of your wifi? Hope to hear a reply, thank you.

  8. Tony

    Hello I am Germany, I have the speedport 7200-7400 I’d really like to be able to set up a second modem for vpn. What would you suggest?

  9. Autotrician

    Hj Guys, I live in the UK and have a BT infinity 2 connecting with the home hub 6 also have a subscription with PureVpn and use this for various devices. What’s my best option for the homehub 6? I have looked at DDWRT routers but I believe I require a modem. Thanks

  10. AllenSmiths

    I have used the RT-AC5300 router with 8 powerful external antennae. No doubt it is the best one.

    Thanks man for this great info. Well Setting up a router with a VPN connection can be useful if you have devices that cannot be connected by themselves, or if you have a lot of devices to connect.

  11. Allan

    Hi Fellers. Hope all is well!. Have you looked at the new offering from Linksys The x6200 adsl modem/router combo. I like the idea of being able to kill 2 birds with one stone.

  12. Ron

    I am using a dual phone line dsl, for speed, Actiontec F2250, and want a router to use VPN. Can this router be flashed and only use one router or is it still good idea to 2 routers


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