NormanS
Premium,MVM
join:2001-02-14
San Jose, CA
 ·Pacific Bell - SBC
1 edit | reply to imric
said by imric  :Can this work if DHCP is disconnected on the LAN? I have a Linksys WRT54GS router and a Linksys WPS54GU2 print server. When I installed the print server it wouldn't work until I disabled DHCP on the LAN and went to static addresses for all LAN members (the print server and two PCs, currently). Actually, when I first connected the print server, I had a Linksys BEFW11S4. That router fried a year or more ago and when I installed the WRT, I never tried re-enabling the DHCP server on the router. Since the problem initially was with the print server, I suspect I need to keep the static IP addresses on the LAN. For static IP addresses on the LAN, I find it convenient to use a router with MAC address reservation. Within the DHCP range of IP addresses, I configure the MAC address of the device I want to have a static IP address along with the IP address I want that device to have. That tells the DHCP server to always assign the same IP address to the device with that MAC address. I am not sure that Linksys routers have that feature.
I'm not sure I understand the discussion about the two subnets, but the solution you described seemed to revolve around DHCP being enabled.
Typically, a router keeps any IP address request on the same side of the NAT boundary if the IP address is within the scope of the subnet on that side of the boundary. So if your modem is on the far side of the NAT, but its IP address is within the scope of the LAN IP address subnet, the router will not pass the packets across the NAT boundary. So you would configure the LAN IP address range on a different subnet. That way, the router does not keep the packets within the router subnet, but passes them through the NAT boundary.
Additionally, I'm in an ex-GTE service area and don't use PPPoE to connect. Verizon uses DHCP to provide the "external world" IP address to my modem. That is, I don't have the WRT router (or anything else, for that matter) log on to my account. I just have the the Internet Connection Type (in the WRT setup) set to "Automatic Configuration - DHCP". Does that make a difference to the technique you described?
I am not sure. If I were to connect my SS4100 to a Verizon DHCP loop, I would have to bridge it. The only other modem options are PPPoE, PPPoA, and "PPP is on the computer". Since DHCP isn't using PPP, none of those options would work.
In theory, it probably should work, but my understanding of the Layer 2 operations it too fuzzy for me to say for certain.
Anyway, I have the 2200 set to Bridge mode (its default was PPPoE) and its DHCP server disabled (per posts in the Verizon Forum FAQ, if I recall correctly) (plus VPI/VCI set to 0/35); otherwise all of its settings are at the defaults.
So, it'd be nice if I could view the stats on my LAN from behind the router and even better if I could do that with the 2200 (but suppose I could go back to the 2100 if that were the only way it could work).
If you can reach the modem through its IP address with a computer, while you have the DHCP connection to the Verizon network, I can't see why you couldn't reach it with a router. But there is Layer 2 activity involved, and I am not sure what will actually happen.
With a PPPoE connection, PPPoE on the router, and the modem bridged, the TCP/IP packet requests are normally encapsulated within the PPP packets (or whatever they are called), so they are not seen for what they are on the WAN side of the router.
But with DHCP, any IP addresses outside of the scope of the LAN subnet mask should be passed to the WAN side of the router. If the packets are within the subnet mask scope of the modem, then they would be kept on that network. So with the router at 192.168.2.1/255.255.255.0, and the modem at 192.168.1.1/255.255.255.0, any packet addressed to the modem should reach the modem.
I doubt it makes a difference, but just in case... the 2200s are not Verizon ISP modems. Mine are model B90-220030-04; the "30" equates to a Bellsouth version of the modem. Verizon editions use "15" in the model number of the Westell modems, from what I learned elsewhere on the BBR. (In case anyone else reading ever gets a hold of a BellSouth modem, you access it at 192.168.1.254 instead of the familiar Verizon modem IP address of 192.168.1.1. It took me a while to figure that out.)
As far as DSL modems go, AT&T, Bellsouth, and Verizon apparently all use G.Dmt modulation, with AT&T and Verizon using VPI/VCI of 0/35, while Bellsouth uses VPI/VCI of 8/35. So they should all be interchangeable. Well, almost. In Verizon regions using DHCP, you need to bridge the modem, as well; if that isn't an option, your stuck with a PPP modem.
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum |
