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***Wireless FAQ***

  • 23-08-2006 2:15pm
    Registered Users Posts: 7,544 ✭✭✭

    This FAQ will be built up to provide answers to the most commonly asked questions on the Wireless Forum. Please look here for a solution to your problem before posting a new thread. If you post a thread about a problem answered here it will be deleted.

    If you want any additions/deletions or modifications made, please PM me.

    1) The three rules of Wireless Networks

    Good article explaining why it will never work as far, as fast or as easy as the makers say it will. ***Currently offline***

    2) Wireless Security

    This article covers what you need to know about securing your wireless connection.

    3) Wireless Setup and Config

    This article covers a lot of questions about setting up a wireless network.

    4) I can't connect to my wireless network. What can I do?

    a) RTFM

    Kinda obvious but many people never bother to read the instruction booklet that came with their wireless equipment. Following the step by step guide is the best way to get your system up and running.

    b) Restart with a clean slate

    If you're having problems configuring your setup it's worthwhile reseting everything to the factory settings. That way you get rid of any configuration mistake you might have made. Also remove any network connections you might have made in your OS.

    c) Switch off any security options

    Many people experience problems when it comes to connecting to a secure network. It is useful to remove any security that is enabled (WEP,WPA, MAC filtering, SSID not broadcast, etc) to see if the device can connect to a vanilla open network. If it can, add one security feature back at a time, that way you can figure out which one is causing the connection issue.

    d) Update software

    Often the wireless equipment you own was shipped with out-of-date drivers/firmware. Go to the manufacturer's website and download the latest drivers for your wireless card and firmware for router/modem/access point. (Just be sure to read carefully the instructions as how to update your device so you don't end up bricking it). This process often improves preformance of the system and removes any bugs or exploits in the software.

    e) DHCP and IP

    DHCP is a method of assigning an ip address to a device as they connect. If you can detect the wireless network, but can't get an ip address, check that dhcp is enabled on the router/access point and that the PC is set to receive an ip address automatically. (In Windows XP: Start->Control Panel->Network Connections. Right click wireless connection and choose properties. Double click "Internet Protocol (TCP/IP)". Make sure "Obtain an IP address automatically" and "Obtain DNS server address automatically" are ticked.

    5) I can connect to wireless network but can't connect to the Internet

    Follow these steps to try and pin point the problem:
    a) Open a command prompt. Start->run->cmd.
    b) In the command prompt type ipconfig /all. If your ip address under your wireless card is or then the problem is that you are not being assigned an ip address by your router. If not, note the ip address listed for "Gateway" and move to step c).
    c) If there is no ip address listed for "Gateway" then this is your problem. If there is an ip listed, type ping x.x.x.x where x.x.x.x is the ip listed for the gateway. If this ping times out, then the problem is that you do not have a valid connection to your router. If you do get a response to the ping, then the connection between your PC and rotuer is fine, so move to step d).
    d) Type ping If the ping times out then the problem is between your router and internet connection. If you get a response, move to step e).
    e) Type ping If this times out then the problem is that your dns servers are not configured.

    6) Can I use my DSL wireless router that I got from Eircom/BT/Smart on my NTL connection?

    Short answer: No, as the NTL cable modem has a RJ-45 output, while a DSL wireless router only has RJ-11 WAN input.

    Longer answer: If the DSL wireless router actually works as a "hub" rather than a switch, it might work. (A hub blindly shares all traffic, regardess of IP address, across all "ports". A switch should only direct traffic to a specific port). If you disable the DHCP server on the DSL router, then a wired client should be able to get a DHCP response from the Cable modem if both the PC and the modem are plugged into LAN ports. And if it works for a wired client, it might work for a wireless client. But it'll only support a single computer - you won't be able to connect two machines to the ADSL router and have them both get on the NTL connection. (Thanks to Foxwood)

    And often the complex nature of the setup means most users fail to get it working. So it's usually better to get a router with a ethernet (RJ-45) wan port such as the Linksys WRT54GL, DLink Di-524 or Netgear WGR614.

    7) Can I use a wireless router with my NTL modem?

    Yes. Connect the NTL modem to the wireless router's WAN port and set the router to receive an ip via DHCP. This should be all you need to do to get it working. However, the problem most people experience is the fact that most cable companies use IP provisioning.

    This means that the NTL modem provisions an IP address to the first Ethernet MAC address the device “sees” or is connected to. That MAC address will be written to the internal table of the cable modem and that MAC address will always be able to connect to the provider network. Given that only one entry in the table is allowed, to connect a new or different user device to the provider network, the entry within the cable modem table must be updated.

    Most cable modems accomplish this table updating by simply powering off the cable modem. As an example, Data Over Cable Service Interface Specification (DOCSIS) cable modem plants follow this protocol. The time a cable modem must be powered off varies amongst cable modems. In most cases, however, powering off the cable modem for ten minutes performs a full clearing of the internal MAC address table. Once the table is cleared, a new user device can be connected to the cable modem. The new user device will populate the MAC address table in the cable modem and receive an IP address from the provider.

    Other cable modems do not release their IP addresses upon cable-modem reset. Instead, they require that a user gracefully release the IP address from any device that has been provisioned with an IP address. To accomplish this task, the user must engage the winipcfg utility (for Win9x and Millennium PCs) or type (from a command prompt) ipconfig /release for Windows NT, 2000 and XP based PCs.

    Therefore if you want to add a router to your network, you need to update the MAC address table by the above method in order to get the router's MAC address in place of the PC you originally connected.

    8) I have a Eircom/BT/Smart DSL modem and I now want to make it wireless. What can I do?

    Option 1: Replace the Eircom/BT/Smart DSL modem with a modem/wireless router combo.
    Pros: Only a single piece of network equipment to use. Easier to setup and configure.
    Cons: ISP won't support the new modem. Possibility of modem not being compatible.

    Option 2: Buy a separate wireless router and connect it to a bridged Eircom/BT/Smart modem.
    Pros: ISP will still support original modem.
    Cons: Slightly more complicated to setup. Another piece of equipment requiring power, space, etc.

    9) What is a bridged modem?

    When configured in Bridge Mode, a DSL modem will act as a pass-through device and allow the workstations on your LAN to have public addresses directly on the internet. Note that in this mode the bridged modem is providing no firewall protection as is afforded by NAT. And you will need a router/firewall server to handle PPPoE Authentication.

    10) Instructions on how to bridge popular DSL modems

    Netopia (Eircom)
    Zyxel (BT)
    Aolynk (Smart)

This discussion has been closed.