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New Member

2 WANs to 1 LAN, keep LAN connectivity

I will be getting business internet service installed in a couple of days and would like to prepare for it.

I will have 2 separate lines:

1 business WAN with 5 static IPs

1 residential WAN, with 1 dynamic IP.

Provider supplies CISCO 851 router for the business line, cheapo cable modem (ethernet out) for the rsidential line.

I already have 6 computers working together in a LAN.

I will configure the 851 to map the 5 static IP's to 5 machines on the LAN, that's a given. I will add switches as needed to expand the number of available ports.

Is there any way to get the 2nd WAN (dynamic IP) to map to the 6th computer in the LAN, while maintaining the LAN integrity so the 6 machines can continue sharing files and printers?

Could the residential WAN tap into the LAN somewhere at a switch perhaps?

I do not need load balancing, do not need to combine the bandwidth from the 2 WANs, and wish to maintain them separate.

I know I could set up 2 LANs ( 1 for each WAN), but those won't talk to each other.

Alternately, I'm contamplating an RV082 dual wan router. would that allow me to do the above?

thank you kindly.

6 REPLIES
Hall of Fame Super Silver

Re: 2 WANs to 1 LAN, keep LAN connectivity

Hello Adrian,

>> Could the residential WAN tap into the LAN somewhere at a switch perhaps?

this is possible but be aware the lan switch can complain from time to time however I did it.

this would allow you to connect the modem ethernet to the switch:

the other 5 pcs will have to use c851 as their default gateway, pc 6 will use the modem ip address

C851 can have two vlans on it so it could be possible also to have the two pcs in two different vlans and to use it for inter vlan routing

pc6 can have a specific route pointing to C851 ip address in vlan2 to reach the other pcs.

Hope to help

Giuseppe

Hall of Fame Super Gold

Re: 2 WANs to 1 LAN, keep LAN connectivity

Hi Giuseppe,

c850 series router can only do one VLANs. The c870 series can do more than 2 (I don't remember the maximum).

Hall of Fame Super Gold

Re: 2 WANs to 1 LAN, keep LAN connectivity

Hi Giuseppe,

c850 series router can only do one VLANs. The c870 series can do more than 2 (I don't remember the maximum).

Re: 2 WANs to 1 LAN, keep LAN connectivity

Dual NICs is another option on the 6th computer.

New Member

Re: 2 WANs to 1 LAN, keep LAN connectivity

OK

Dual NICs

Will Win XP pro accomodate these 2 NICs in the way I expect it to, or will I need additional configuration.

I mean could win XP use both NICS simultaneously ( surf the web thru dynamic IP #6, while saving a file to the LAN)?

Incidentally, dual WAN routers seem ready for 2 just scenarios: combine bandwith of the 2 WANS, or use only one WAN, until it fails, then switch to using only the 2nd one.

Is it even possible for such a router to keep 2 WANs separate, and map them to separate machines?

Re: 2 WANs to 1 LAN, keep LAN connectivity

Based on the info you've provided I'm suggesting you install two NIC's on computer number 6. Essentially making computer number 6 a Router. NIC 1 will connect to the cable modem and the cable modem will be your default gateway. NIC 2 will connect to your LAN and will communicate with the other 5 computers.

Using a 2nd NIC is a band aid and i'm just offering it up as an altenative. You can do everything you want to do with the right router and configuration.

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