What about router platforms? Will I have a chance to test it with 1841 or 2800 
routers? At least IPExperts lab gives an example of statefull IPSec HA with 
2811 routers.

Eugene
Sent from iPhone

On Jun 22, 2012, at 7:57 PM, "Kingsley Charles" 
<[email protected]<mailto:[email protected]>> wrote:

Yes, you need a reload for HA to work.

With regards
Kings

On Sat, Jun 23, 2012 at 12:10 AM, Eugene Pefti 
<[email protected]<mailto:[email protected]>> wrote:
Bruno and all,
I have a stupid question to ask. The white paper given below says that IPSec HA 
is supported only by high-end routers.
I didn’t have any problem adding all required commands on 1841 router but 
didn’t test it yet because I still don’t understand all the nitty-gritty 
details about it specifically about routers to be reloaded for the 
configuration to take effects.
Moreover the configs in this white paper miss “local-port” statement that 
should go before “local-ip”.
I don’t know who in the sound mind will remember all the commands required to 
set interdevice communication to enable stateful IPSec failover.
Hoping that VPN availability guide is accessible during the lab in case such a 
task
http://www.cisco.com/en/US/docs/ios-xml/ios/sec_conn_vpnav/configuration/12-4t/sec-state-fail-ipsec.html

Eugene

From: 
[email protected]<mailto:[email protected]>
 
[mailto:[email protected]<mailto:[email protected]>]
 On Behalf Of Bruno Silva

Sent: Thursday, June 21, 2012 11:12 PM
To: 
<[email protected]<mailto:[email protected]>>
Subject: Re: [OSL | CCIE_Security] Need help understanding "no-alias" NAT option

Hi Eugene,

Apart from who wrotte the solution for this task, what I think is not the case, 
I have also came across this task and for some reason this is not the only 
wrong thing on it. This is a ipsec ha solution that you're trying to configure 
and for some reason the solution not only does not work as  it is also 
confusing in some parts. Since I came across a lot of problems with this 
solution this is what helped me a lot:

http://www.cisco.com/en/US/technologies/tk583/tk372/technologies_white_paper0900aecd80278edf.html

Hopefully you can find the same help I found in this document.

BR,
Bruno Silva

Enviado via iPad

Em 22/06/2012, às 00:27, Mike Rojas 
<[email protected]<mailto:[email protected]>> escreveu:
Yep,

Anyone who think differently is very appreciated...

Mike
________________________________
From: [email protected]<mailto:[email protected]>
To: [email protected]<mailto:[email protected]>; 
[email protected]<mailto:[email protected]>
Subject: RE: [OSL | CCIE_Security] Need help understanding "no-alias" NAT option
Date: Fri, 22 Jun 2012 03:17:55 +0000

Unfortunately it doesn’t make sense to me either because R2 runs in the routed 
mode.

I believe it’s just the faulty solution in the first place. I’m not going to 
point fingers who the solution provider is but it’s not IPExperts ;)



From: Mike Rojas [mailto:[email protected]]
Sent: Thursday, June 21, 2012 8:13 PM
To: Eugene Pefti; 
[email protected]<mailto:[email protected]>
Subject: RE: [OSL | CCIE_Security] Need help understanding "no-alias" NAT option



Hi,

Assuming that the router 2 is not on transparent mode, taking it out it wouldnt 
make much difference, because the packet will be routed to the next hop (R2), 
assuming that there is a route for the network of the ASA to be behind router2 
on the HSRP routers. It would make sense if they are all on the same broadcast 
domain.

Mike.

________________________________

From: [email protected]<mailto:[email protected]>
To: [email protected]<mailto:[email protected]>; 
[email protected]<mailto:[email protected]>
Subject: RE: [OSL | CCIE_Security] Need help understanding "no-alias" NAT option
Date: Fri, 22 Jun 2012 03:05:49 +0000

Hi Mike,

Yes, I’m familiar with it. It’s the same as you say “sysopt noproxyarp” on the 
ASA.

My question is about why would you do it? Can someone will give me a good 
example?



I’m doing a task and it asks to configure a peer for a pair of HSRP routers. 
I’ll have to give a sketch of the topology to make it more or less clear:



R1----+--- R2-----(163.1.132.0)-----ASA-----R6

R3----|



So to be precise R1 and R3 should have their IPSec peer set to 163.1.132.113 
which is ASA interface.

The solution configures static NAT on R2 binding 163.1.132.113 to R6 loopback:



ip nat inside source static 6.0.0.1 163.1.132.113 no-alias



If R2 will stop responding to ARP requests sent to 163.1.132.113 how the whole 
thing will work ?



Eugene





From: Mike Rojas [mailto:[email protected]]
Sent: Thursday, June 21, 2012 7:54 PM
To: Eugene Pefti; 
[email protected]<mailto:[email protected]>
Subject: RE: [OSL | CCIE_Security] Need help understanding "no-alias" NAT option



Hey Eugene,

Are you familiar with proxyARP? Basically, the router will answer arp for any 
address that is on its range assigned to a particular interface associated with 
a NAT right? well, this command will stop the router so it doesnt do it anymore.

Mike

________________________________

From: [email protected]<mailto:[email protected]>
To: [email protected]<mailto:[email protected]>
Date: Fri, 22 Jun 2012 02:44:22 +0000
Subject: [OSL | CCIE_Security] Need help understanding "no-alias" NAT option

What are use cases of this “no-alias” NAT option. All references I found in 
Cisco docs say little to me.



Quoting:



• Autoaliasing of Pool Addresses:

Many customers want to configure the NAT software to translate their local 
addresses to global addresses allocated from unused addresses from an attached 
subnet.

This requires that the router answer ARP requests for those addresses so that 
packets destined for the global addresses are accepted by the router and 
translated.

(Routing takes care of this packet delivery when the global addresses are 
allocated from a virtual network which isn't connected to anything.) When a NAT 
pool used

as an inside global or outside local pool consists of addresses on an attached 
subnet, the software will generate an alias for that address so that the router 
will answer

ARPs for those addresses.



This automatic aliasing also occurs for inside global or outside local 
addresses in static entries. It can be disabled for static entries can be 
disabled by using the "no-alias" keyword:.

ip nat inside source static <local-ip-address> <global-ip-address> no-alias



Why would the router NOT reply on behalf of those global addresses ?



Eugene

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_______________________________________________
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Are you a CCNP or CCIE and looking for a job? Check out 
www.PlatinumPlacement.com<http://www.PlatinumPlacement.com>

_______________________________________________
For more information regarding industry leading CCIE Lab training, please visit 
www.ipexpert.com<http://www.ipexpert.com>

Are you a CCNP or CCIE and looking for a job? Check out 
www.PlatinumPlacement.com<http://www.PlatinumPlacement.com>

_______________________________________________
For more information regarding industry leading CCIE Lab training, please visit 
www.ipexpert.com

Are you a CCNP or CCIE and looking for a job? Check out 
www.PlatinumPlacement.com

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