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Have an 1841 router with the following interfaces:

0/0 0/1 AUX

on the right side, believe it's slot 1, there's an add-on interface FE0 (shows up as 000).

Does this allow a multi-WAN configuration? i.e. can I use 0/1 for WAN1 and FE0 as WAN2 out-of-the-box or does this require additional licensing and/or another add-on interface in slot 0?


Need a dual WAN configuration to do policy routing only (no load-balancing/HA) so I can send certain traffic out the WAN2 connection for policy/security reasons. Will be doing SNAT for the inside traffic going out this interface as well.

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2 Answers 2

up vote 2 down vote accepted

If it's just going to be routing, it doesn't really care whether any given network is a LAN or WAN. Three interfaces? Two WANs and one LAN will work just fine. No licensing required.

If you're going to be doing NAT, things become more difficult.

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Well it will support two WANs, but you are going to need one more interface for your LAN. (AUX is not a LAN interface, rather a PPP dial-in interface).

You will need no additional licensing. Depending on how you set up both your WANs (i.e. if you do two bgp peering with full tables), you might need to buy more memory. You might want to explain more how you are going utilize both WANs for help with that as well, but in general these are pretty capable routers.

For the additional WIC that will be your LAN, you might want to get a 4 port ethernet H-WIC. These are like built-in switches, but you can set them in a mode where each one acts like an individual lan port (With certain limitations with things like QoS). This will probably come in handy at some point when you want to implement a DMZ.

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You might want to hold off a bit to make sure several people confirm that this is the right choice. In particular I think Murali Suriar knows a lot, and you might want to ask in #cisco one as well. – Kyle Brandt Apr 30 '10 at 19:55
Thanks, Kyle: always looking for good IRC channels. – gravyface May 1 '10 at 12:58
Actually Kyle, I have 3 interfaces: 0/0 (LAN), 0/1 (WAN2), FE0 (WAN1) – gravyface May 1 '10 at 13:21
Ah, sounds like you are good then. Mikey (+1_ is right, an interface is really just an interface as far as LAN/WAN goes. Although the speed of it might make it more suited for one thing or the other. For example, if you have a 5Mbit Internet connection and two lans and then two GE ports and one FE port, you probably want the WAN on the FE port. – Kyle Brandt May 1 '10 at 14:39

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