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Connecting a router to BigPond or Optus Cable

Since the Telstra Heartbeat system was retired back in 2006-07 both Telstra and Optus now use an almost identical authentication system. However, installing a router to gain Internet sharing &/or security onto a Cable ISP isn't always straight forward and there are a few tricks and traps for the unwary.

  • What's the difference between a modem and a router?
  • Where to buy Cable modems
  • Have you got the right type of Cable modem to plug into a router?
  • How to find a suitable router
  • How to configure a Router for Cable
  • What's the difference between a modem and a router?

    Firstly, it's important to understand the difference between a modem and a router. A modem provides the link (bridge) between your ISP and your home. A router takes that connection and shares it to the PCs and other devices on your home network using a process called NAT (Network Address Translation). Routers may also have other features like firewalls to keep the hackers out and other advanced security features to restrict access to certain material on the web, built-in Wireless Access Points, built-in VPN servers, VoIP hardware and more. Many routers even have the modem part built-in as well, which I call "all-in-ones". Routers that don't have built-in modems will need a modem plugged into them to form the bridge between the ISP and the router. Modems in this function do not perform any NAT, security, wireless, VoIP or anthing else. They are just "dumb" bridges passing everything through to the router they're connected to, and from the router back to the ISP.

    Check out my Router FAQs for more information about routers.

    Where to buy Cable modems

    Unlike ADSL, Cable modems can only be sourced from the Cable ISPs in Australia*. You cannot buy a Cable modem or an all-in-one-cable-modem-router from a retailer. The main reason for this is that the Cable modem has to be registered on the Cable ISP's network before it will work.

    * While I know of no retail or wholesale sources for Cable modems within Australia, you can however buy a second hand Cable modem privately from eBay etc and then contact your ISP to have the modem registered on the network. This can save a few dollars if you need to replace a damaged modem when you're out of contract. However, Cable ISPs will only accept certain brands and models of modems so do not buy one, particularly from overseas sellers, without first checking with your ISP first if they will accept it. Also be wary of old tech DOCSIS 1.0 etc modems. These will still usually work as far as I'm aware but may not perform the best. Rule of thumb - if in doubt, check with your ISP before you fork over your cash.

    Now, to share your Cable Internet connection on a network you can buy plenty of routers that you can plug your existing Cable modem into, provided it's the right type of Cable modem.

    Have you got the right type of Cable modem to plug into a router?

    The first thing to consider when looking for a router for Cable is the type of Cable modem you have, and by that I mean if it's a plain old bridged modem (with no router features) or an all-in-one modem-router.

    Modem-Routers (aka All-In-Ones): If you've got an all-in-one (Modem+Router+Wireless) modem such as the Netgear CG814WG, it is already a router so you already have everything you need. These tend to be reasonable products if your needs are only basic such as browsing the web and checking email with up to 10 or so connected devices (PCs, iPhones, Media Centres etc). However, they usually fall short if you have a larger or busier network or you need to do stuff like add an ATA for VoIP, gaming, P2P downloading, increasing wifi performance or VPNs. In these cases you're better off getting a standard bridged modem* to plug into a router of your choice.

    * With some All-In-One products it may be possible to configure it in "bridging mode" so it becomes a plain bridged modem which you can then successfully plug into another router. While I don't have specific details on how to do this (or if it's possible) for every product out there, for some general background information about bridging all-in-one modem-routers see my router FAQ 3.6. For more detailed information for your particular product, try googling its model No (eg CG814WG) + "bridge mode" and you'll usually turn up a few forum posts with instructions from people who have either been successful or not as the case may be.

    Bridged modem: If you've got a plain modem like the Motorola SB5101 you're laughing. These can be plugged straight into a router without any special configuration.

    Once you've figured out if you have a bridged modem, or how to get one either by asking your ISP about an exchanging your all-in-one for a plain modem or working out how to bridge your all-in-one, it's time to choose a router.

    How to find a suitable router.

    The main feature that a router must have is an ethernet WAN port. There are many products available which have both built-in ADSL modems and ethernet WAN ports and these are fine for either Cable or ADSL (bearing in mind this often means sacrificing one of the LAN ports though so you may only be left with 3 instead of 4), but if it only has an ADSL modem and does not feature an Ethernet WAN port it will not be suitable for Cable.

    An easy way to find routers with an ethernet WAN port is to use my Find-A-Router tool and tick the box for either "One" or "More than One"* beside 10/100 Ethernet WAN Ports or Gigabit WAN Ports. (10/100 WAN ports are usually cheaper than routers with Gigabit ports but still plenty fast enough for Cable internet. Gigabit is the best option though if you plan to upgrade to NBN any time soon. Choose either 10/100 or gigabit at a time though, not both.)

    * "More than one" is for people with two or more broadband connections they wish to run simultaneously.

    That will produce quite a large list on its own so choose some other features and/or set a price range to narrow down the selection a bit.

    As a rule of thumb for general home use, products from popular brands like Billion, D-Link, Draytek and Netgear in the $50-150.00 bracket with a 10/100 or Gigabit WAN port and N300 or above wireless are great choices.

    (Note:Any products that attract too many complaints come off the online shop and won't show a price in the Find-A-Router tool so if you see a price it should be fine for the job regardless of the brand).

    For more advanced features like VoIP, Gigabit WAN ports and dual band wireless, look in the $150-$300.00 bracket. Billion, Fritz and Draytek are the most popular choices in the VoIP category. If you're chasing fancy dual band wifi standards like N750, N900 or 802.11ac, Netgear, D-Link and Linksys are the way to go there.

    For business or more commercial use, or larger home networks (ie more than 20 connected devices or more than 3 or 4 gamers/torrent users), go above $300. This is where you get products with better build qualities and the processing power to handle a larger number of connected devices without bogging down or rebooting constantly.

    Note: Be aware that many of the products with built-in ADSL modems as well as ethernet WAN ports have what is known as a configurable LAN port, aka "EWAN". Using these will mean losing one of the LAN ports to the Cable modem so you'll only be left with three but other than that they're fine for the job.

    How to configure a router for Cable

    Once you have your Cable modem plugged into the Internet port on your router you'll need to follow your router's quick start guide to log into it to start configuring it.

    Once logged into the Router you can choose the setup wizard (if it has one) or just go straight to the section where you enter your ISP settings. This would normally be called Basic Settings such as on a Netgear Router, or WAN or Internet Settings on most other products.
    What you're looking for to make it connect to your ISP is an option called "DHCP", "ISP assigned" or an "ISP without a username & password" or similar.
    Here is an example showing a typical Netgear Router -
    And here is an example showing a D-Link Router -
    And here is an example showing a Draytek Router -

    Note: If you're on BigPond Cable and you see an option called "BigPond" such as in the D-Link example above, avoid it. This is for the old Heartbeat system which no longer exists.

    Any IP address settings should remain as automatic (also called DHCP and ISP assigned)
    Any DNS settings should also remain as automatic.
    If there is an option to change the Mac address leave that with the factory default for the time being.

    Click the Apply button or any other options required to save the settings and allow the router to reboot if it asks for it.

    Once the router has rebooted test you are online by opening a Command Prompt Window* by clicking Start > Run > Type "Command" > Click "OK" >
    Type "ping -t" > press enter.
    If it's not connected you'll get replies saying "Request Timed Out".
    If the Router is off-line or rebooting you'll get replies saying "Destination unreachable"
    When it has connected you'll get replies saying "Reply from bytes=32 time=22ms TTL=248" or something like that.
    Hit Control-C to stop the pings.

    * If using a non-windows PC just try surfing the web to see if you're online.

    If you're getting replies to the pings but cannot surf any websites, check your DNS and/or browser proxy settings. More information in the Router Troubleshooting FAQs.

    The Secret Trick - Power Cycle the modem.

    If you're not getting replies to the pings and therefore not online, switch the modem off (at the wall, not just the standby button on the top of the modem), wait 20 seconds or so then turn it back on again. Wait until all of the lights indicate it's booted and synced up again then do the same to the router and you should be up and away. (Switching the modem off clears any memory it might have had with the PC or previous router it was plugged into. Rebooting the router after that allows it to attempt to connect to the ISP again.)

    Note: Switching routers off and on too quickly can sometimes cause them to throw wobblers or reset back to their factory default settings.

    Spoofing the MAC (media access control) Address

    This is last resort only, but if switching the modem off as above didn't get things working try "spoofing" the MAC address of the old Network Card that was previously connected to the Cable modem.

    To find this MAC address, see http://ozcableguy.com/glossary.asp#mac
    Write it down and then find a section in the Router that allows you to specify a MAC address for the WAN port and copy it there. (Note: Some Routers allow various fiddling with MAC addresses on LAN ports and this is not what we're looking for here. It must be referred to as WAN or Internet and not LAN or Local.)

    Switch the Cable modem and router off and then back on after a few seconds pause and check if you're online now.

    Warning: If you do decide to spoof the MAC address of a previous router or network card, one thing you don't want to happen is for the old router or network card to end up plugged into the same ISP at the same time. So if you decide to sell or give away the old one, make sure you get the new router working on its default MAC address first (it will usually connect by itself with the default MAC address if you just plug it in and leave it for a while).

    If you're still not online go away for 30 minutes then check again. If still no good, look up your router manufacturer's Australian website and contact their support section. They will step you through the settings and/or diagnose the product as faulty and give you instructions for its repair or replacement under warranty.