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New Member

Help with 2811 router

We are setting up a dual ISP network, here is what we have:

Router = 2811

Sprint T1 on Se0/0/0

Sprint T1 on Se0/1/0

XO 10mb network on FA0/1

FA0/0 going to firewall

I have routes:

ip route se0/0/0

ip route se0/1/0

And all is good.

When I add

ip route fa0/1

the internet goes to a crawl and sometimes goes away all together. As soon as I remove the route to fa0/1 bam we are back on the internet. Is there a issue with using the fa0/1 to talk to the XO network? The XO comes from a Haturas box which takes 10 POTS lines and convets them into a 10mb network.

If I hook a laptop directly to the XO network all is fine. Could it be that all my ip addresses on the router are Sprint ip's?


Re: Help with 2811 router

hello ciscoadmin,

you cannot get the packets routed on the XO network, with sprint IP addresses.. the uplink service provider will not route your packets, thinking it as an alien packet .... you can do manual load distribution, by using source based routing with NAT on the XO IP subnet..

Or if you have got to do automatic load sharing and failover, you got to run an external routing protocol called BGP.. BGP is used for multihoming. you will be required to get an ASN number and Public IP pool for this !!!

Hope this helps.. let us know if you need anything else on this..


Cisco Employee

Re: Help with 2811 router


I would never suggest to run default routes in the situation when you have 2 different ISP's feeding the internet to you.I would rather look for more controlled and filtered way for sending the traffic from 2 different ISP's.The idea behind this is that with default routes you dont know that traffic will hit which router and will use which link to go out forexample if you have a slow wan link and a high speed wan link, with default routes you dont have control over sending a majority of traffic thorugh high speed wan link and a little low traffic over the slow speed wan link. Another problem here would be of Assysmteric routing in which tarrfic for internet might use one ISP link and the return traffic will come all the way via internet traffic through the second ISP.This is where the slowness comes into the picture.

If I were you, I would have thought of using NAT and PBR (policy based routing).I would first look at the kind of traffic, users, applications that I have to go the outisde world. Once the traffic is determined I would see the traffic distribution of the users over the two links. I would use my application, mail traffic to go thorough one link and internet and other traffic to use another link.I will make both the links as back up of each other.In case of one of the link goes my all the traffic will use the other link. I would suggest to implement proper QOS and rate limiting to drop the unwanted traffic.


Policy Based Routing:


HTH,Please rate if it does.

-amit singh

New Member

Re: Help with 2811 router

Thank you for the info it makes sense I will look into it.

New Member

Re: Help with 2811 router

I agree with the NAT, I did not setup the original network but now I need to get it right. Here is a little more about the network.







Internal network

Now is there anyreason why the outside port of the pix needs to be a public ip address? I should be able to make it a non public and then the fa0/0 on the router one hop up from the pix again private ip address and then work NAT out on the router?

New Member

Re: Help with 2811 router

Hi Amit. i found your message above very interesting. i would need your help regarding my network. i have a network with 2 dynamic adsls from the same isp, load balanced with cef and 2 route maps. everything would work better if i could assign a few applications(port based) to go out from 1 adsl and a few others from the second. any suggestions???

thanks in advance

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