Cisco → [HELP] Dual DHCP WAN with tracking help

I am appealing to this group because Cisco Tac has been less than helpful. Does anyone have a working config with Dual DHCP WAN connections with a successful tracking and failover-failback scenario? Specifically with static route setup. The cisco tracking example uses 1 dhcp and one static connection. They also assume static gatways on both connections. This is clearly not the case with with both my DHCP connections since a change in ip can also mean a change in gateway ip. Appreciate any guidance.

Hang10

I ran into a similar problem when I had two ISPs - one with ADSL (PPPoA) and the other with a DHCP connection. Couldn't find anyway to get it to work using SLA. If someone knows the secret config could it would be appreciated if they could post it. (OER isn't available on the 87x so I can't try that.)

I was thinking about you after your other thread when I was setting my router up for dual connections.

Reading the Cisco documents I noticed the problem I think you are having now. I presume you are using "set ip next-hop dynamic dhcp" for setting the next hop. The documentation from 12.3(8)T states "The set ip next-hop dynamic dhcp command currently supports only a single DHCP interface. If multiple interfaces have DHCP configured, the gateway that was most recently learned among all interfaces running DHCP will be used by the route map."

I haven't seen anything that says this limitation has been removed (although that doesn't mean that it hasn't).

If this is indeed your problem I can only think of two solutions. Get yourself a DSL card and then you can specify a static route for the DSL connection (assuming the next hop is constant) or get a cheap router between your current router and the dsl modem so that once again you can specify a static route to the second router for the DSL connection.

Michael there shouldn't really be any problem with what you are trying to achieve. I presume you have read »www.cisco.com/en/US/prod ··· 62d.html

If you have any old configs you tried why not post them in a new thread here? I'm in the middle of doing a lot of work on my own router set up so I don't know if I could contribute much in the next week but you never know and there are others here who have done this before.

This is really turning out to be a bad deal. After working through many possible workarounds it looks llike it is not possible. Unfortunate, considering they market these things with dual WAN capability.

hang10

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Michael there shouldn't really be any problem with what you are trying to achieve. I presume you have read »www.cisco.com/en/US/products/sw/···62d.html

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Yes. I use that document and it works for every case except PPPoA (Qwest uses PPPoA, PPPoE may be available at some locations but it isn't supported). I did note that the only configuration which isn't mentioned and doesn't have an example is PPPoA. Even when the PPPoA link is configured as the backup path all traffic is sent through the PPPoA link. It works fine if I use an 827 or something similar to deal with the DSL line and then assign a static route to the 871 going via the 827. The main link obtains its address via dhcp. But no go using an 877.

I'll post the configs I tried later this weekend.

Thank you for your help.

Any guess at how often your default route that you get from dhcp changes? Can you configure a static route based on the next-hop for one of the two ISP's, and set up the DHCP configuration recommended in the Reliable Static Routing Paper? Or set up two static routes and monitor both, according to this doc:

»tcpmag.com/qanda/article ··· lsID=348

Does the router send a log if one of the tracked routes dies? That would let you know that either the connection dropped, or your ISP pulled a fast one on you and changed your IP or route. I know it's a hack, but you didn't say you only wanted fully-baked ideas....