cable modem as backup

[scotto27]

Can't seem to remember the IOS piece of this. I have a T1, I'm adding a cable modem. I want all traffic except http to continue flowing out the t1 by default, http to flow out the cable modem by default. Then each to provide failover for each other in case they are down.

Can anyone point me in the right direction again.

Thanks,

Scott

 

[rtfmdude]

Scott,

This is going to be fun. first, I think you'll need to policy route your traffic to split the port 80 stuff from the rest. Then I think you'll need to use object tracking to flip between the 2 interfaces reliably(since the cable connection can go down without the actual ethernet interface on the router going down since you're using a cable modem). Then I think you'll need to do a little more policy routing to get nat to work over both interfaces. heh.

policy routing:

http://cisco.com/en/US/tech/tk364/technologies_configuration_example09186a00801f3b54.shtml

object tracking for redundancy:

http://cisco.com/en/US/products/sw/iosswrel/ps5413/products_feature_guide09186a00801d862d.html

somebody's config for dual-nat using policy routing:

http://www.hojmark.org/x/dual-nat.txt

 

[scotto27]

Hey, thanks alot. It was policy routing I was looking for from before I believe. I'll have a look in that direction and see how it turns out for me. One step at a time, you know.

Thanks,

Scott

 

[clearodef]

Hi Scott,

I just posted a thread awhile ago in regards to connecting a cisco router to a cable modem. Since you've already done it, I assume that you will know the answer to my question. Hopefully you can help out. I'm starting on my CCNA and thought it'd be best to learn this at home because work is just too hectic to learn this in depth.

I just want to connect my internal network to e0 and my router to the cable modem. My question is how do I do that part: router-to-cable modem. At work, we have serial interfaces and T1 cards. Do I need a certain card as I figured the T1 card is made for T1 lines. My cable modem only support ethernet so I immediately thought the T1 card except for the fact that it's T1.

Thanks in advance!

 

[scotto27]

You would use an ethernet interface as well to connect the cable modem to the router. The router I'm using has e0 to internal, e1 to cable modem and s0 to t1.

Scott

 

[clearodef]

So this would assume that I have a router that has TWO ethernet ports, eg, the 2611 or 2621 series routers? I noticed this after reading some more after I had posted. It didn't occur to me that certain models came dual ports (e0 & e1) even though we have them at work. Haha. Thanks!

 

[JOAMON]

Hey clearodef...
What model router do you have....?

 

[clearodef]

well, i was about to buy a 2507 router. but i don't think i could actually use that for my test production network. instead, i'm now shopping for a 2611, preferrably 2611xm. so, what was on your mind? any suggestions?

 

[JOAMON]

2611 good solid router.....only drawback is no fastethernet port. One way to add one would be NM-1FE for lan side. Ethernet ports can be set on full-duplex but you will have issues unless connected to a Cisco switch which is hard set to 10 full as well.
The 2611XM router will support Ciscos serurity device manager software. It is very useful for configuring the more advanced features of the router. See link below:

http://www.cisco.com/en/US/products/sw/secursw/ps5318/products_data_sheet0900aecd800fd118.html

Good tool to have if you are having trouble with a test config you could use SDM to auto-configure it and then see what it did different to make it work.