Load Sharing Between Two Default Routes

[randms2610]

Hello everyone, 

I want to ask a question, is it possible to have a load sharing between two default routes?

Let's say I have 1 router with 3 interfaces.

- int f0/0 connected to ISP1 

- int f1/0 connected to ISP2

- int f2/0 connected to LAN segment

Right now, I have configured the default route to ISP1 and ISP2

ip route 0.0.0.0 0.0.0.0 1.1.1.1 (let's say 1.1.1.1 is the default gateway to ISP1)

ip route 0.0.0.0 0.0.0.0 2.2.2.2 (2.2.2.2 is the default gateway of ISP2)

I also have dynamic NAT configured on interface f0/0 and f1/0, it's working fine for each interface.

From the "show ip route 0.0.0.0" command output says that network 0.0.0.0/0 can be reached via 1.1.1.1 and 2.2.2.2

But I see that the router keep using f0/0 as the exit interface to the interent (I see the NAT translations is only using the IP of interface f0/0).

Does this means that interface f1/0 is never used to connect to the internet?

I thought cef load-sharing is enabled by default. But why it keep using only one exit interface?

Any help would be very useful.

Thanks

PS: when I issue shutdown command on the f0/0 interface, the router is using the f1/0 interface for forwarding packet to the internet, but this is not what I want. I actually want it to be load-shared.

[Mohinder Singh Rawat]

Hi,

You can use policy based routing to load balance 2 default route with NAT applied, see below article for detailed explanation.

https://supportforums.cisco.com/document/32186/dual-internet-links-nating-pbr-and-ip-sla

Rate the post if find useful.

Thanks

Mahi

[randms2610]

Hi Mahi, thanks for the answer :)

that's close enough... on the link you provided he divided the traffic based on destination port.... but I want it to be possible to load-balance/load-share same types of traffic a.k.a the same destination port, I guess need it to be balanced in round-robin like in GLBP...

example:

client1 accessing www to 8.8.8.8 via ISP1

client2 accessing www to 8.8.8.8 via ISP2

client3 accessing www to 7.7.7.7 via ISP1

client4 accessing www to 6.6.6.6 via ISP2

...and so on

is it possible to achieve result like this without adding more router to the topology?

i'm sorry if I asked like a newbie... :(

[Bilal Nawaz]

Is your CEF enabled? Sh ip cef 0.0.0.0 0.0.0.0

sh cef interface