Dual ISP with IPSecVPN

[santiago.jem]

Hi Experts,

I've been doing some research on how to configure an ASA with Dual ISP with IPSec Tunnel going to HQ.

Here is the outline that I think I need I may need to do.

1.  Configure the Redundant Link, which led me to this:

http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a00806e880b.shtml

Fair enough, I was able to grasps the concept on the above link.

2. Configure VPN with HQ_ASA. This seems to be the tough part.

What I would like to do is that Primary Link (15 Mbps DSL) will form VPN Peer with HQ when it is UP (used tracking as stated above).

When the Primary Link fails Secondary Link (5 Mbps DSL) will form a New VPN Peer with HQ

On both instances, the HQ_VPN Peer will have the same IP Address.

Looking forward for your response guys.

Thank you.

[Julio Carvajal]

Hello Jemel,

You will need to configure to crypto maps on the other site as you cannot use the same Ip address because each interface as you know its on it's own broadcast domain.

So

On site A configure SLA, and 2 crypto maps one on each interface

On site B configure 2 crypto map one for interface A ( the active ) and one for interface B ( The secondary )

Regards,

Julio

[santiago.jem]

Thanks Julio.

This seems to be feasible. Do you happen to know other documentation for implementing such?

I've been actually working on 5510s just a little over 4 months and man, this is intense!

Regards,

Jemel

[Julio Carvajal · Accepted solution]

Hello Jemel,

Yes, I understand what you mean but no I have not seen any documents related to this but I could help if required.

Again on site A just configure the normal stuff ( 2 interfaces, the SLA stuff, create 2 crypto maps and apply one in the primary interface and the other one on the secondary)

On site B just create 2 crypto maps ( One will set the peer to be the ASA1 Primary link, The second one will be the ASA1 Secondary link) Isakmp will try to communicate to both interfaces but as only one is active only one tunnel will be generated

Let me know if I was clear enough, if not do not worry just let me know and I will be more than glad to help you

Regards,

Julio

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[santiago.jem]

Thanks Julio.

This has been very helpful. I am on the right track with this.

Regards,

Jemel

[santiago.jem]

Hi Julio,

I haven't implemented this yet, doing a little testing using gns3.

It came to me, what will happen the NAT configurations I have?

It seems that the protected networks, (siteA inside network and siteB inside network) will likely be OK.

What about the other traffic like internet traffic? How will it be NATed?

Thank you.

Regards,

Jemel

[Julio Carvajal]

Hello,

On site A you will need to create nat for the primary and the secondary link, just in case the primary goes down.

So you will be natted to the primary as soon as it's up

Regards,

[juan-ruiz]

Santiago,

According to your diagram HQ only has one link to the internet is this correct?

If so then you should only need one crypto map applied to the outside interface and specify two peers on the crypto map statement, peer 1 15 mbps ISP, peer 2 5 mbps ISP.

Julio, please correct me if I’m wrong or if we can configure two crypto maps to the same interface.

Thanks,

Juan

[Julio Carvajal]

Hello Juan Ruiz,

You can only have one crypto map on each interface but each of the crypto map can have more than one entry ( so you will set 2 peers,etc)

Regards,

Julio

[santiago.jem]

Hi Julio,

That's understood, so there will be 2 NAT entries, one for each interface whichever is active.

Hi Juan,

Yes, I came across the same scenario. It also mentioned just having to create 1 crypto map with 2 peers in it.

https://supportforums.cisco.com/thread/2060152

I'm planning to implement this though and the other as suggested by Julio.

Thanks.

[Julio Carvajal]

Hello

Correct Santiago

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[santiago.jem]

I've actually tried and implemented the project but there seem to be an issue.

There was nothing that was configured on the:

Configuration > Device Setup > Routing > Static Routes

But, when I checked on the device, and tried show route there's seem to be an entry in the routing table:

ciscoasa# sh route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

       * - candidate default, U - per-user static route, o - ODR

       P - periodic downloaded static route

Gateway of last resort is x.x.x.x to network 0.0.0.0

C    a.a.a.a 255.255.255.0 is directly connected, inside

C    x.x.x.x 255.255.255.248 is directly connected, outside

d*   0.0.0.0 0.0.0.0 [1/0] via x.x.x.x, outside

ciscoasa#

May I know why is it that the new interface that I added which is PPPoE is not listed as CONNECTED?

And also, what caused the default route to be d*?

Hoping to here from you soon.

Thank you.

[Julio Carvajal]

Hello Jemel,

If the interface is up, you should see the network directly connected.

RIght now looks like the ASA does not have the interface properly configured. if you do a sh interface ip brief what is the status of the interface?

[Julio Carvajal]

Hello Jemel,

Are you using the protocol IKEV2 or is that your intention?

I mean looks like you are using IKEv1, I think you are referring to phase 2 (Ipsec).

The problem you are having now it's because of the configuration between both sides.

Please do the following

-Check the Diffie-Hellman group on each side

-Check that both sides has a pre-shared key configured ( On router B you need to have 2, one for each peer)

Regards,

Julio

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[santiago.jem]

Hi Julio,

I've checked on the DH, and both sides are on Group 2.

I will check on the pre-shared key if both sides are correct.

Thanks.