2 internet connections 1 router

Discussion in 'Tomato Firmware' started by apinunt, Dec 30, 2007.

  1. apinunt

    apinunt LI Guru Member

    I have 2 internet connections, one a 2 way fixed IP Satellite connection, and a recently acquired dynamic IP ADSL connection. I have the latest Tomato FW installed, and am totally ignorant of how I can set up what ever needed which would allow me to unplug the existing connection from the Satellite terminal internet access to the WRT54GS router, and replace it with the wire coming from the new ADSL internet access, requiring no setup changes be made in the router.
    The router is in the Gateway mode and I am uncertain if I need to use the router mode to do this. The router setup shows info related to the WAN connection which belongs to the Satellite terminal connection, and I assume this would present a conflict with the ADSL connection as the info would not be the same, so I don't know what to do with that and removing the info kills my connection.
    Any help would be greatly appreciated. And I do not wish to make use of DHCP.
  2. LLigetfa

    LLigetfa LI Guru Member

    Well... the two connections use two different technologies. The ADSL I assume, would be PPPoE. You would have to setup a PPPoE connectoid on the router and PPPoE is by its nature DHCP based so there is no getting away from DHCP.

    Just to be clear on this, you want to keep both ISP services but only want to use one at a time and you want to switch manually between them by moving the WAN cable without having to change any settings in the router?
  3. apinunt

    apinunt LI Guru Member

    Only recently has ADSL become available and I have a annual contract on the Satellite, which means I have some months left before I can give it up without cost. Also neither is 100% reliable so I would like the ability to switch to the one which is working when the need arises, and would like it to be simply moving the WAN cable.

    I'm having a little difficulty understanding some of the acronyms such as PPPoE, which the ADSL line is using, and if I understand correctly, DHCP must apply in the case of the WAN IP with the ADSL connection, but the ADSL modem was also set up to use DHCP in setting the IP of the connected computer, which in this case always remains to be, or the first available address in the range allowed. I would like to return the computer IP back to and it appears that should be possible in the ADSL modems setup in the LAN Clients Tab, by entering an IP address, Hostname, and MAC Address, and checking the Reserve box, for each computer that will be connected to the router. If I understand this correctly that would eliminate DHCP from being used, except for the WAN side which I have no control over.

    It is the router I am having difficulty in understanding what needs be done. Should it be in using the Gateway or the router mode? And an additional complication is what info should the router contain related to the WAN connection that would allow either the Satellite or the ADSL connection to be recognized and used? I thought maybe entering the IP of the Satellite terminal would work but it kills the internet access. And the Aztech ADSL modem uses a setup access IP of which is the same as the Linksys WRT54GS router.
  4. LLigetfa

    LLigetfa LI Guru Member

    You can google or wiki for PPPoE.

    We need to get few things cleared up first.
    Does the sat give you a public IP on the WAN port? I'm thinking that it does and that is why you have it in gateway mode.

    Is your ADSL customer premise equipment simply a modem in bridge mode, or is it a router/NAT device? If you connect a PC to it, does it give you an IP without setting up a PPPoE connectoid? Does it give you a public or private IP withor without PPPoE?
  5. apinunt

    apinunt LI Guru Member

    Thanks, and I have been googling and reading for the last several days which in many cases has only increased my questions.
    Initially I purchased the Satellite connection with only a single computer connection, and had requested a fixed IP address at an additional cost. I later purchased a 2nd computer and then a Linksys WRT54GS router, and after much trial and error managed to get it to work, mostly by looking at the setup page of the Satellite terminal and looking for matching information to enter into the routers setup page. The WAN port I entered into the router was what I found labled as the Ethernet Link in the Satellite terminals setup page. As for the gateway mode, I believe that was what the router had set already and I never tried changing it. So although everything works, it may not be the best method. I was happy just to get a working connection on both computers and had no problems adding a 3rd one later.

    I believe the ADSL equipment, (Aztech ADSL 2/2+ Ethernet/USB router), is a Router/NAT device, and I watched the installers enter as Connection type PPPoE. I have a dynamic IP address on the internet as they told me fixed IP addresses were not possible. As to it being a public or private IP, I am not certain how to determine that.

    The installers had some difficulty in getting it to work, and were unable to answer most questions I asked, they only spoke Thai and when I asked for the user name and password to log in and change settings they gave me the uid and password used to establish my internet connection, which is plainly visible on the pages not requiring a log in. It wasn't difficult to figure out the password, and later I found it was a default and easily found on the internet. There are many setup screens in the ADSL terminal, and I'm not sure if I will have to make changes there in addition to in my router in order to accomplish what I would like to have.
    I have been playing with the router on the other computer to see if I can eliminate having the satellite terminals WAN information entered into the router and still be able to access the internet. I think that will be a conflict if it remains in the router and I try to connect the router to the ADSL modem which uses a different WAN IP. That's why I question if I should have set the router in the router mode instead of the Gateway mode.

    Thank you for your help, and I'll try to answer any further questions as best I can, but with somewhat limited knowledge.
  6. HennieM

    HennieM Network Guru Member

    Understanding the difference between a DHCP client and a DHCP server seems key (in addition to all the other things...).

    When a PC connected to a network, get a dynamic IP address via DHCP, that PC is a DHCP client. Similarly, when your WRT GETs an address via DHCP, whether this is over PPPoE or some other protocol, your WRT is a DHCP CLIENT. This is completely separate and independend from being a DHCP server.

    A DHCP server is the 'thing" that hands out those dynamic IP addresses to DHCP clients. Your WRT can-, or not-, be a DHCP server. If you turn off the DHCP server on your WRT, it can still act-, or not-, as a DHCP client, getting it's dynamic IP address over PPPoE or somewhere else.

    Your WRT should still be in gateway mode when connected via the ADSL line. Gateway mode means "route and do NAT", while router mode means "route and don't do NAT", and this has nothing to do with how you connect to the internet, be-it via cable, satellite, ADSL, or whatever.

    The PPPoE or PPPoA or whatever protocol is used to connect your ADSL modem to the internet should be specified by your ISP.
  7. LLigetfa

    LLigetfa LI Guru Member

    Having the WRT in gateway mode when the upstream router is already in gateway mode creates what's known as a double-NAT. Now there are a lot of people doing that and not complaining but in certain circumstances, a double-NAT can cause grief.

    The reason I asked about public versus private addresses was to determine if/where NAT'ing is taking place. I think it is safe to assume that the ADSL router is NAT but I'm still not clear on the SAT link. If you are entering a private IP on the WAN port of the WRT, then it is also probably NAT. If that is the case, you may be able to configure both upstream devices to use the same private IP and a common DNS and therefore be able to switch between the two transparently.

    The gateway versus router thing might be a moot point if double-NAT is not causing you any grief.
  8. apinunt

    apinunt LI Guru Member

    The last 2 posts are a little (lot?) over my head. I assume WRT refers to the WRT54 router?
    I don't know if this helps or not, but I began with 1 computer and a Satellite terminal and paid for a fixed IP 58.xxx.xxx.xxx, which I have had for a few years now.
    When I purchased another computer and the Linksys router, I inserted the router between the 2 computers and the satellite terminal and began making entries in the routers setup until I was able to access the internet. Afterward I could still remove the router from the picture and connect either computer to the satellite terminal and use the internet. I had assigned a different IP to each of the 2 computers but it didn't matter which I connected to the satellite terminal, they would both work with no changes necessary. I assume the Satellite terminal just passes info without needing to know the computer IP? And I assume it only becomes important when more than one computer is sharing a connection, and it becomes the routers responsibility to associate traffic with a particular computer?

    The ADSL modem has but one computer connection, yet is called an ethernet/USB router on the box. Essentially I would like it to work similar to the Satellite terminal, meaning I could connect either computer to it without having to set anything and it recognize the computer without assigning it an IP address, but using the one that is already assigned to the computer.

    It appears to me that the router needs to be set up in some way where it sees the satellite terminal and the ADSL modem as simply an internet connection, and not require the WAN IP of either the satellite or the ADSL be entered in the setup, OR is there a common address that could be set by me in the ADSL which would match the satellites IP so that either could be accessed without necessity of making setup changes in the router?

    WRT54GS setup ( now contains:
    MAC Address 00:14:BF:F7:78:8C (I believe this belongs to the Satellite Terminal?)
    Connection Type Static IP (I believe this refers to my WAN IP?)
    IP Address 58.xxx.xxx.146 (My pingable address on the internet?)
    Subnet Mask
    Gateway 58.xxx.xxx.145
    DNS 203.xxx.xx.xx, 203.xxx.xx.x, 202.xx.xxx.xx
    MTU 1500

    Which I entered from the Satellite terminals setup ( display:
    USB Link
    Ethernet Link 58.xxx.xxx.145
    DNS Servers:
    IP Address
    Address Range
    58.xxx.xxx.146 - 58.xxx.xxx.146 (a single IP - my fixed IP?)

    I just found a tab on the Satellite terminal's setup that shows NAT checked as disabled.
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