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Routing Table for sharing INTERNET on 2 networks ?

Discussion in 'Networking Issues' started by dri66, Nov 6, 2005.

  1. dri66

    dri66 Network Guru Member

    Hello,

    I am new on this , sorry for the stupid question.
    The setup I have :
    WRT54GS Firmware Version : v4.50.9
    ROUTER ADDRESS : 192.168.1.1
    SUBNET MASK 255.255.255.240

    4 computers on network 1
    IP 192.168.1.2
    IP 192.168.1.3
    IP 192.168.1.4
    IP 192.168.1.5

    4 computers on network 2
    IP 192.168.1.18 NO DHCP
    IP 192.168.1.19 NO DHCP
    IP 192.168.1.20 NO DHCP
    IP 192.168.1.21 NO DHCP

    The 2 networks has to be separated , this work well.
    Network 1 can have INTERNET.
    Network 2 can NOT have INTERNET :(

    I have try to give GATEWAY 192.168.1.1 on network 2 , but this does not help.

    I have try this in the routing table :
    Destination Subnet Masl Gateway Interface
    192.168.1.16 255.255.255.240 0.0.0.0 LAN & Wireless
    192.168.1.0 255.255.255.240 0.0.0.0 LAN & Wireless
    81.83.72.0 255.255.252.0 0.0.0.0 WAN (Internet)
    0.0.0.0 0.0.0.0 81.83.72.1 WAN (Internet)

    Can anyone give me some link on routing tables ?
    Thank you for your help ;)

    Best Regards,
    Didier.
     
  2. cgondo

    cgondo Network Guru Member

    This is interesting since i am also learning myself. I can understand that you separate the two subnets....but there might be implication on NAT?

    I am keen to know the answer to this question and a workaround if any
     
  3. DocLarge

    DocLarge Super Moderator Staff Member Member

    Look at "Scenario 2" in the link below:

    http://www.linksysinfo.org/modules.php?name=Forums&file=viewtopic&t=9941

    If I forgot to mention, Linksys routers come configured with dynamic routing enabled, so when you connect a second router via the configuration I've outlined, your routing table is automatically filled in for you.

    I'm running this configuration right now.

    Doc
     
  4. cgondo

    cgondo Network Guru Member

    but i think the difference is that he is using 1 router and not two routers. Say he has another switch connected to one of the LAN ports of the WRT and another switch attached on another LAN port of the WRT.

    i am guessing it is something to do with the NAT only being able to translate one network and not two different sub networks.

    Anyone can give a clearer explanation?
     
  5. Monoman

    Monoman Network Guru Member

    Remove the GW ?

    Have you tried removing the default gateway ("router") address for clients on network #2? If the clients have no default gateway, and a single connected NIC (or multiple NICs w/o running a routing protocol) then this should work.
     
  6. cgondo

    cgondo Network Guru Member

    He said that he tried giving it the gateway which i think means that he has trid no gateway before.

    Anyway....why do you think that it will work if there is no gateway in network 2?
     
  7. Monoman

    Monoman Network Guru Member

    No GW

    He said that he tried giving it the gateway which i think means that he has trid no gateway before.
    Anyway....why do you think that it will work if there is no gateway in network 2?


    Disclaimier: I reserve the right to be completely wrong.

    1. You may be right but it was not explicitly stated.

    2. He said network #2 was to be denied Internet access. I also assumed network #2 was not to be able to communicate to network #1. (based on: "The 2 networks has to be separated , this work well.)

    The way I understand IP routing is IF a device's IP stack determines that a destination IP is not on the same subnet (calculated by doing a logical AND on the IP and subnet mask) THEN it will direct the traffic to the gateway(s) set in the routing table. So if he removes the default gateway on the clients and they have no other static routes then no traffic should be sent to the router.

    By "separated" does he mean to eliminate broadcasts between the two networks or all traffic between the networks.? Routers typically dont block *ALL* traffic between networks unless there are Access Control Lists in place or static routes to override default/dynamic routes.

    The poster should be clearer about what we are trying to accomplish. :)

    I'm gonna stop now before I ramble even more.
     
  8. cgondo

    cgondo Network Guru Member

    what he wants it....for the two networks to be separated locally however both CAN access the internet.
     
  9. Monoman

    Monoman Network Guru Member

    doh!

    The 2 networks has to be separated , this work well.
    Network 1 can have INTERNET.
    Network 2 can NOT have INTERNET Sad


    So it looks like I misread the subject AND the subtlety of the sad face.
    </hitting head with clue by 4>

    I think I derailed this thread enough. Well it was fun knocking the cob webs loose in the old brain. :)
     

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