1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

The best way to receive, provide and send signal ?

Discussion in 'DD-WRT Firmware' started by MBChris, Jun 14, 2005.

  1. MBChris

    MBChris Network Guru Member

    @all
    im wondering if anyone could provide me a good solution for the following scenario with 4 WRTs ... all running DD-WRT-22 pf 4

    WRT1 is ADSL Point about 3km away
    WRT2 should recive signal at channel 1 from WRT0
    WRT3 should provide the signal for wireless clients channel 7
    WRT4 should send the signal to the next AP on channel 13

    Now my Questions:
    What is the best Config for this ?
    especialy the WRT2-4, how should i configure them Gateway/Router ?

    WRT1 is providing DHCP, DNS and INET

    If it is not clear i could draw a sketch for better understanding

    thanks in advance
    Chris
     
  2. jagboy

    jagboy Network Guru Member

  3. MBChris

    MBChris Network Guru Member

    Sorry jagboy, i don't want to have WDS here because rhere are many clients around which would be impact then !

    And .... i dont like to set all clients for a WDS-Mesh

    thanks anyway for your answer !

    greets Chris
     
  4. DevilStick

    DevilStick Network Guru Member

    Why should you have to set up the clients for WDS? Wouldn't the 4 AP not be enough? How else would you want to realize it?

    Are only WRT 1 and WRT 2 connected wireless or all APs? If all should connect wireless to its neighbour, you will get problems with using different channels.

    You could set it up like this

    WRT 1-))) (((-WRT 2 ---- WRT 3 ---- WRT 4

    WRT 1 = Client mode chan 1
    WRT 2 = AP mode chan 1
    WRT 3 = AP mode chan 7
    WRT 4 = AP mode chan 13

    This would work. Alternative you could set up a wireless bridge between WRT 1 and WRT 2

    You should use 'Router mode' on WRT 2-4 and only 'Gateway mode' on WRT 1, since last mode make NAT-translation and assuming a server on WRT 4 wants to listen on port 80, you would have to set up 4 port forwardings. One on each WRT. With only WRT 1 as gateway, you have only to set up one forwarding and then the packet is routed to the concerning client/server.
     
  5. MBChris

    MBChris Network Guru Member

    @DevilStick

    Thank you, thats exact the answer to my question.

    yes, only WRT1-WRT2 are connected wireless. As i said, WRT2 receive the signal to one Point, at this point WRT3 provides the signal for wireless clients and WRT4 send the signal over long distance to another Point (with, again 3 WRTs)

    Ok, when i now setup the WRT2-4 as ROUTER what about the Network definition. Ive DHCP running on WRT1, so all clients get there addresses from WRT1. So my thoughts for the configuration as follows:

    WRT1:
    Internet: PPPOE
    Internal IP: 192.168.0.2
    Subnet: 255.255.255.0
    Gateway: 0.0.0.0
    DNS1: 0.0.0.0
    DHCP: ON/192.168.0.100 + 50 Adresses
    Mode: Gateway
    Firewall: ON
    Wireless Mode: AP
    Channel: 1
    WEP: 128
    WDS: LAN and MAC from WRT2
    SSID: TRANSIT1
    Local DNS: activated


    WRT2:
    Internet: Disabled
    Internal IP: 192.168.0.3
    Subnet: 255.255.255.0
    Gateway: 192.168.0.2
    DNS1: 192.168.0.2
    DNS2: 0.0.0.0
    DNS3: 0.0.0.0
    DHCP: OFF
    MODE: ROUTER/RIP2
    FIrewall: off
    Wireless Mode: AP
    Channel: 1
    WEP: 128
    WDS: LAN and MAC from WRT1
    SSID: TRANSIT1
    Local DNS: deactivated

    WRT3: (wired to WRT2 over LAN-Ports)
    Internet: Disabled
    Internal IP: 192.168.0.4
    Subnet: 255.255.255.0
    Gateway: 192.168.0.2
    DNS1: 192.168.0.2
    DNS2: 0.0.0.0
    DNS3: 0.0.0.0
    DHCP: OFF
    MODE: ROUTER/RIP2
    FIrewall: off
    Wireless Mode: AP
    Channel: 7
    WEP: 128
    SSID: OURNET
    Local DNS: deactivated


    WRT4: (wired to WRT3 over LAN-Ports)
    Internet: Disabled
    Internal IP: 192.168.0.5
    Subnet: 255.255.255.0
    Gateway: 192.168.0.2
    DNS1: 192.168.0.2
    DNS2: 0.0.0.0
    DNS3: 0.0.0.0
    DHCP: OFF
    MODE: ROUTER/RIP2
    FIrewall: off
    Wireless Mode: AP
    WDS: LAN and MAC from WRT5 (Next point)
    Channel: 11
    WEP: 128
    SSID: TRANSIT2
    Local DNS: deactivated


    ... is that correct ?
    If a client connects wireless to WRT3 the client could get DHCP-Addr from WRT1 ?

    What if i connect to WRT3 with another WRT in Client Mode, i think the WRT gets also an DHCP-Addr, but the clients (wired) behind this Client-WRT couldn't get DHCP-Addrs from WRT1, right ?

    Hmmmm
    alot of questions, sorry but i want to clarify this for myself

    Greets
    Chris
     
  6. DevilStick

    DevilStick Network Guru Member

    Ah, you disable the WAN ports of WRT 2-4. So everything is bridged and it does not matter whether you use gateway or router mode.
    So you have one network with wrts acting as AP and cascaded switches.

    That will work.

    But it won't work when you connect another WRT as client to WRT 3, since client WRTs do not allow any wireless clients. Only direct attached wired clients to this client WRT will get a dhcp from WRT 1.
     
  7. MBChris

    MBChris Network Guru Member

    Exactly what i want ! .... sofar .....

    BUT, i think if i connect a client-WRT (wireless) to WRT3, the internal Network must be different :( So the attached, wired Clients are not receiving the DHCP from WRT1 ..... or .... is there a way to fix that also ?

    Devil .... THX for reply
    greets Chris
     
  8. DevilStick

    DevilStick Network Guru Member

    Hmmm, that's right. A client WRT uses the wireless 'port' as WAN. So a WDS would be better, since you can bridge on layer 2, pass through dhcp and on both WRTs wireless clients can connect.

    But maybe you can fix something via telnet, so that by a client WRT configuration the wireless 'port' gets bridged to the ethernet ports.

    I found a link where it is explained how to change vlans and bridging of ports. With this HOWTO you should be able to configure a bridge between wireless and ethernet when running WRT in client mode.
     
  9. sillynickname4me

    sillynickname4me Network Guru Member

    dhcp forwarding

    If you happen to run openwrt you can install a dhcp forwarder.
    'ipkg install dhcp-fwd' should do the trick.

    Linking all together into one big segment is not going to be nice performance wise if you happen to have many broadcasts (ie, windows systems trying to discover their network neighborhood)

    No idea if this is available on dd.
     
  10. MBChris

    MBChris Network Guru Member

    Re: dhcp forwarding

    Thank you ! Ill try it, but i also been told that there is another way to do it over well existing GUI of DD-WRT/Alchemy.
    A "friend" of mine suggest to deactivate the VLAN-tagging, deactivate the Firewall and switch to Router Mode. Then the Client-WRT should let DHCP pass to the LAN-Ports.

    I will try that also this evening .... or may i have the risk to brick it with this config ?

    greets
    Chris
     
  11. sillynickname4me

    sillynickname4me Network Guru Member

    Re: dhcp forwarding

    If you can achieve this using a GUI and without having to change to different firmware thats nice indeed.

    With regards to routing mode, the issue is that DHCP requests are broadcasts that stay within the subnet directly connected to the machine that sends them, they won't get routed. If you want them to be passed on to a dhcp server on another subnet, you have to run a forwarder on the router between the subnets. So while I agree with the setup your friend suggests, you will still need to run a dhcp forwarder on the WRTs that are acting as a router.

    I guess dd gives you a way to access the commandline, in that case you could check if you have /usr/sbin/dhcp-fwd on it.

    With regards to bridging, if its just 2 or 3 WRTs, you can bridge everything together without much regard , beyond that it depends a lot on what you are going to do with them and how well you plan your network layout and configure filtering on the bridges

    You could decide to bridge the segments together but explicitly filter out all (ip) broadcasts except for dhcp at each of the WRTs interfaces (note that you will need ethernet broadcasts still for the arp protocol to work). If all you want to offer is ip servces for internet access you'll be fine that way and could try building a network consisting 10+ WRTs acting as bridges. Your 54mbps wireless 'backbone' should not have much of a problem supporting the amount of traffic required for this. This requires setting up filtering and a bit more planning and networking knowledge.
     

Share This Page