How to convert a wireless ADSL router/modem to just an access point and a modem and use an external Linux box as a router (internet gateway)

04
2013-08
  • Marwan

    My home network setup is just a typical one. A "dump" box from Vodafone containing everything (ADSL modem/router + 4-port Ethernet switch + Wireless access point).

    Since I am kind of a techie, I don't like that kind of setup and I need to be able to configure everything by hand (NAT using iptable rules, etc.). So, I decided to setup an external Linux box as the router (Internet gateway) for the rest of the LAN according to this guide: http://www.gentoo.org/doc/en/home-router-howto.xml

    So, my question is: Is it possible to just leverage the Access point and the ADSL modem functionality in the dump box while using the external Linux router so that I don't need to buy both (modem + AP) separately?

    Googling on the issue of the AP I know it can be done by disabling DHCP in the dump box and using a DHCP server in the Linux gateway with an IP address range that doesn't include the IP address of the dump box. The issue with me is that I want to do BOTH things (The AP and modem).

    The thing that confuses me the most is how to bypass the PPPoE configuration in the dump box so that the one in the Linux box can take effect without conflict, specially that the configuration interface for the dump box doesn't contain any controls for disabling PPPoE. It just contains fields for the parameters (like username, and password, etc.). Or am I a bit pessimistic and things would just work once I configure the hosts on the LAN to use the new Linux gateway?

    Any help would be really appreciated. And thanks for your time.

    • Answers
  • JRobert

    You should be able to just chain them. I have an Apple Time Capsule behind my provider's ADSL gateway (modem/router/AP). The Time Capsule warned me about double-NATting during setup but allowed it, so I effectively have two NAT firewalls. It's been in use for several years with no ill effects I can see.

  • mgorven

    The way that ADSL is usually handled is to put the modem into bridged mode, and run a PPPoE client on the Linux box. The modem then simply provides transport between the Linux box and the access concentrator, and the Linux box has the credentials for creating the connection and is responsible for routing traffic through the ADSL connection.

    In terms of DHCP you want to setup a DHCP server on the Linux box, and disable the DHCP servers on both the modem and the API. You probably want to give the modem and AP static IPs on your subnet so that you can access them for management.


    • Related Question

    wireless networking - Convert a Linksys WAG54GP2 ADSL router into Access point only to extend my Wifi range
  • Preet Sangha

    I have a wireless lan running on my ASDL2 connection. The router (Seimens Gigaset sx763) is provided by the ISP and is generally good. However I have couple of dead spots at the far end of the house and since I have my old router sitting in the drawer I thought that I'd try to convert it into simple WAP.

    However downloading the manual from linksys it seems to be that the manual is from an earlier firmware, but the very first option on the very first page seems promising:

    Wan Mode: Router or ADSL

    However after this I'm a bit lost. I know that the wireless card on this box will need a mac address and it must get its address from the master router (I thought static might be best).

    However the again the manual is out of date I have the option of

    DHCP: ON or OFF or RELAY

    I've not even got to the more complex options yet.

    Question is can this device even work this way (seems like it but I cannot find any docs on it), and if so how?

    Edit: Having now fiddled around I'm of the opinion that this cannot be done.


    • Related Answers
  • pavsaund

    Update: After looking through the product manual of your Linksys WAG54GP2 router, I'm convinced there is no way to set it up as a repeater / extender using the default firmware.

    Update2: The options you mention, do not have anything to do with making the router an extender. But rather how it should function within the physical network you are plugging it in to.

    Since you mention A few deadspots, maybe you should consider getting a stronger antenna? Depending on the actual obstacles in the way, and distance to these deadsposts, this may actually remove the need for using the link WAG54GP2 as a repeater.

    If you'd still like to make the WAG54GP2 work as a repeater for the wirless network, then what you'll most probably be needing is custom firmware to enable this functionallity (if it's supported) for your Linksys Wireless router like:

    This howto gives instructions of how to upgrade the WRTG54G2 to dd-wrt

    Also check out some of the threads on Superuser that cover the topic.

  • Area 51

    IMO, most people do not realize that consumer WiFi routers can be used just as WAP i.e. not use the WAN port on the unit and follow this:

    Cascade one of the LAN ports of your WiFi router with your central switch using a regular/cross over (which ever is applicable) CAT5 cable, and give the WiFi unit a static IP number. Disable DHCP on the WiFi device if there is another DHCP server already on your LAN. You can follow this procedure for any numbers of WiFi routers/APa - just ensure that you give them unique static IP addresses.

    Give a different SSID and WPA2 pass phrase to your WiFi AP. Done.

    I have done such setups and it works! No need to muck around with any special firmware.