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2 static default route for lan and wan in a router

Newone
Level 1
Level 1

Previous, routerA has wan and lan connection, for wan using static default route and lan using static route. A next hop router (routerB) at lan having a different segment. Can routerA do another static default route to lan as it already have it for wan? What is the impact of this?

 

Provider (wan) ----- routerA----routerB (lan)

1 Accepted Solution

Accepted Solutions

Hello


@Newone wrote:
Hi paul, as i imagine at lan side have multiple segment and/or multiple router. Are we able to do it or there is workaround for this?

Absolutely by specific static routes between the two routers or dynamic routing advertising each rtrs subnets with each other.


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This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

View solution in original post

8 Replies 8

luis_cordova
VIP Alumni
VIP Alumni

Hi @Newone 

 

When a packet originating in LAN is destined for the Internet, then some packets will be sent by the WAN interface and others by the LAN interface, creating greater consumption in your network, both in your LAN and in your bandwidth to the Internet.

 

Regards

Hello,

 

out of curiosity I labbed this up. With two default routes, one pointing out the WAN and the other out the LAN interface, I lose all connectivity, even when per-packet load-sharing is configured on the outgoing interfaces. Not sure if this is consistent across all platforms, but it doesn't seem like a good idea...

Hi, thanks your feedback. It there any term in cisco for this?

Hello


@Newone wrote:

Previous,routerA has wan and lan connection, for wan using static default route and lan using static route. A next hop router (routerB) at lan having a different segment. Can routerA do another static default route to lan as it already have it for wan? What is the impact of this?

 

Provider (wan) ----- routerA----routerB (lan



Why would you want to to have another default static route pointing towards rtr1 lan ?


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Hi paul, as i imagine at lan side have multiple segment and/or multiple router. Are we able to do it or there is workaround for this?

Hello


@Newone wrote:
Hi paul, as i imagine at lan side have multiple segment and/or multiple router. Are we able to do it or there is workaround for this?

Absolutely by specific static routes between the two routers or dynamic routing advertising each rtrs subnets with each other.


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Hi Paul,

Thanks for your advise. May I know why we cannot perform the static default route at wan and lan in this case?

The reason it doesn't work is that any packet coming into Router A sees two routes, both pointing out a different interface. How is the packet supposed to know which route to take ? It is like asking somebody for directions and being told that you can go left or right at the same time. You can have a default route on Router B pointing towards Router A, and a default route on Router A pointing towards the WAN, but not two default routes on Router A pointing out towards two Router B and the WAN at the same time...

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