Hi Tyson

I have no issues in configuring ASA to allow traceroute.

But I am not able to get the picture of where to use inspect icmp error. I
tried scenarios but it didn;t work.

Just wanted to understand why ASA have provided the inspect icmp error
option.




With regards
Kings




On Mon, Jan 25, 2010 at 5:55 PM, Tyson Scott <[email protected]> wrote:

>  Kingsley,
>
>
>
> Are you wanting to allow traceroute in both directions?
>
>
>
> Regards,
>
>
>
> Tyson Scott - CCIE #13513 R&S, Security, and SP
>
> Technical Instructor - IPexpert, Inc.
>
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> *From:* [email protected] [mailto:
> [email protected]] *On Behalf Of *Kingsley Charles
> *Sent:* Monday, January 25, 2010 5:01 AM
> *To:* Piotr Matusiak
> *Cc:* [email protected]
> *Subject:* Re: [OSL | CCIE_Security] inspect icmp error
>
>
>
> Hi Piotr
>
>
>
> This is the ACL on the outside interface.
>
>
>
> ciscoasa# sh run access-list 120
> access-list 120 extended permit udp any any range 33434 33464
> access-list 120 extended permit icmp any any echo
> access-list 120 extended permit icmp any any unreachable
> access-list 120 extended permit icmp any any time-exceeded
> access-list 120 extended permit icmp any any echo-reply
>
>
>
> With regards
>
> Kings
>
> On Mon, Jan 25, 2010 at 3:28 PM, Piotr Matusiak <[email protected]> wrote:
>
> Kings,
>
> Have you opened a hole for UDP packets (traceroute) in the outside ACL?
>
> HTH,
> --
> Piotr Matusiak
> CCIE #19860 (R&S, Security)
>
>
>
>  2010/1/25 Kingsley Charles <[email protected]>
>
> Hi Piotr
>
>
>
> I did try that before sending this mail. The traceroute just prints "*"
> and no Ip addresses are present.
>
>
>
> How can you traceroute to an unstranslated IP address from a lower security
> level interface.
>
>
>
>
>
> With regards
>
> Kings
>
> On Mon, Jan 25, 2010 at 2:51 PM, Piotr Matusiak <[email protected]> wrote:
>
> Hi,
>
> You must traceroute private (untranslated) IP address of the host in the
> inside network to see the difference.
>
> For example:
>
> (lo0)R1 -10.1.1.0- (out)ASA(in) -10.2.2.0- R2(lo0)
>
> Assuming you have the following translation on the ASA:
> static (in,out) 10.1.1.99 10.2.2.2
>
> Run the following command on R1:
> traceroute <R2-lo0>
>
> You will see that ASA translates ICMP time-exceeded or unreachable IP
> address to 10.1.1.99 (if you have icmp error inspection enabled). If not,
> you will see untranslated IP address of R2 (10.2.2.2).
>
>
> HTH,
> Piotr Matusiak
>
>
>  2010/1/25 Kingsley Charles <[email protected]>
>
> Hi all
>
>
>
> Can someone please let me know, where would we actually use "inspect icmp
> error". I am not getting the right explanation.
>
>
>
>
> http://www.cisco.com/en/US/docs/security/asa/asa80/command/reference/i2.html#wp1726194
>
>
>
>
>
> With inspect icmp error enabled, I tried to IOS traceroute from outside to
> a host behind the ASA. With "set connection decrement-ttl", the internel
> address is revealed.
>
>
>
> Do we use "inspect icmp error", to reveal the actual internal IP address?
>
>
>
>
>
>
>
> With regards
>
> Kings
>
>
>
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