Configure Failover/Redundancy for internet connection

[beatdown]

Our internet connection consists of two bonded T1's (2 serial interfaces) on a Cisco 1841 Router. We have a Watchguard Firewall behind the router, which is connected via crossover cable.

For redundancy, we'd like to get another T1 from a different ISP, and hook it up to a spare Cisco 2611 that we have laying around.

Can anyone tell me how I could configure things so if the main internet connection and/or the Cisco 1841 fails, it will automatically fail over to the other internet connection on the Cisco 2611?

I think this can be done with HSRP, but I'm not exactly sure how to configure the routers for this, or how to physically hook it all together?

Thanks!

 

[DanInRaleigh]

..how are you peering with your isp's next hop?

..assuming you have a default static route to isp's next hop

(ip route 0.0.0.0 0.0.0.0 1.1.1.1 1) everything is being routed to your primary isp..with metric 1

..answer you question...yes you can have redudancy with that 2600 to another isp..with the help of a couple of static routes...

hookup that 2811 to that 2600 (via ethernet etc

ip route 0.0.0.0 0.0.0.0 1.1.1.1 1 (your main isp)
..everything will route to your primary isp with distance metric of 1..

...when that primary route fails you will have a floating static route with higher metric...and everything will be rerouted because that is the next best route...

ip route 0.0.0.0 0.0.0.0 2.2.2.2 121 (your 2600 is next hop and that is hooked to your backup isp)

..of couse the 2811 is still single source of failure if hardware problem but you will have connectivity redundancy if that primary t-1 fails...

..atleast i think it will work. ;-)..

..also are you hosting websites..etc; could be resolution situation there..minor detail..



CCNP,CCSP,MCSE,Sec+,Net+,A+...

 

[beatdown]

Thanks Dan. After doing some more research, I've learned how to use HSRP, so even if one router fails, I'll still have connectivity to the internet.

I've come to realize that the big problem is that we will soon have our E-Commerce web servers on site here, and even if we have a second T1 line to a differnt provider, and HSRP with two routers...I need to figure out how traffic will get routed from the internet, through the backup T1's ISP, to our web server if the primary router/T1 fails, since the web server will use an IP from the block we get from the primary ISP.

From what I understand about this (which isn't much), we would need to use BGP, so the new route to our web server would propagate through the internet if the primary router/T1 fails. But in order to do this, wouldn't our company need to buy it's own block of IP Addresses (as opposed to using the IP's you normally get from your ISP), and then work with our two ISP's to have them setup routing and BGP on their equipment, to route to our network?

Does anyone know if I am correct about this, or is there an easier way to do this?

Thanks

 

[lgarner]

Yes, except for buying addresses. Check with your providers. You will need at least a /24 and you will need to purchase your own ASN.

 

[DanInRaleigh]

....isnt there such a thing as redundant dns..for example if the dns server that is pointing customers to your website detects that the ip address is down, it will repoint to another preconfiged IP address?
..i guess it matters who you are using for your dns..
..then you dont have to purchase IP subnet blocks. or private AS.
..just throwing ideas around...

CCNP,CCSP,MCSE,Sec+,Net+,A+...

 

[hair76solid]

what about the load sharing ? is therea way to share the load between two of the connections

 

[plshlpme]

the easier way would be to multihome the servers by giving them a secondary ip address that belongs to isp 2

then at the dns level you could add a second host entry with the other ip...

this may require some Policy based routing to get it to work properly but if cost is a concern would be the cheaper way to go..

BGP with your own netblock and AS would be the most reobust way to go though.


for load sharing... pbr again would make it easy to do..

http://www.cisco.com/univercd/cc/td...s124/124cg/hirp_c/ch20/h_pbrtrk.htm#wp1027258