Addd an inbound acl permitting udp 500.

With regards
Kings

On Mon, May 21, 2012 at 2:59 AM, Eugene Pefti <[email protected]>wrote:

>  Hello guys,****
>
> I kindly ask for your fresh pair of eyes to help me understand what’s
> wrong with IPSec traffic traversing the ASA.****
>
> The setup is trivial:****
>
> ** **
>
> **(1.1.1.1  **– loopback0) R1 ----(inside)---- ASA ----- (outside) ------
> R6 (6.6.6.6 – loopback0)****
>
> ** **
>
> The task asks to configure a tunnel between R1 and R6 but the specific
> requirement is not to use any ACL on ASA to allow IPSec.****
>
> Ok, I did everything that is required and I assume the solution should
> work when the traffic is originated from R1 to R6 providing I have a
> static mapping on ASA and “inspect ipsec-pass-thru” in the global policy.*
> ***
>
> ** **
>
> Static (inside,outside) 1.1.1.1 1.1.1.1****
>
> policy-map global_policy****
>
> class inspection_default****
>
>   inspect ipsec-pass-through****
>
> ** **
>
> Then an interesting things are observed. I originate ICMP traffic from R1
> sourcing it from loopback0, the tunnel comes up (at least I see QM_IDLE on
> both routers in the ACTIVE state)****
>
> I’m seeing that R6 sends ICMP replies to R1 loopback0 sourcing them from
> loopback0 as well while I debug ICMP. But the ASA reports the following:**
> **
>
> ****
>
> %ASA-4-106023: Deny protocol 50 src outside:6.6.6.6 dst inside:1.1.1.1 by
> access-group "OUTSIDE-INBOUND" [0x0, 0x0]****
>
> ** **
>
> Which absolutely doesn’t make sense as there’s “ipsec-pass-through”
> inspection configured. Note that it doesn’t work (counters are 0)****
>
> ** **
>
> ASA1(config)# sh service-policy global inspect ipsec-pass-thru ****
>
> ** **
>
> Global policy: ****
>
>   Service-policy: global_policy****
>
>     Class-map: inspection_default****
>
>       Inspect: ipsec-pass-thru _default_ipsec_passthru_map, packet 0, drop
> 0, reset-drop 0****
>
> ** **
>
> Then goes the most interesting part. I temporarily allow ESP traffic on
> ASA outside interface with an ACL****
>
> ** **
>
> access-list OUTSIDE-INBOUND extended permit esp any any****
>
> ** **
>
> And of course the traffic between routers loopback starts flowing
> flawlessly. Then I remove the above said ACL. Pings still are being
> exchanged between R1 and R6. Then I clear the crypto session on both
> routers and start sending pings again.  This time it works without an ACL
> and what is the most important this time is that the IPSec inspection
> starts working as well (see counters for the corresponding inspection
> policy, I had them highlighted in *red*)****
>
> ** **
>
> ASA1(config)# sh service-policy global inspect ipsec-pass-thru          **
> **
>
> ** **
>
> Global policy: ****
>
>   Service-policy: global_policy****
>
>     Class-map: inspection_default****
>
>       Inspect: ipsec-pass-thru _default_ipsec_passthru_map, *packet 12*,
> drop 0, reset-drop 0****
>
> ** **
>
> Can some please explain me why the ASA acts like that ? Why doesn’t  the
> “inspect ipsec-pass-through” rule kicks in in the first place? ****
>
> Eugene****
>
> ** **
>
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