Hi Daljeet,

 

Global ACL's - One of the main motivation to create global ACL feature was
to minimize the number of ACL's created during checkpoint to ASA migration
and to create a flow based policy. These provide interface independent
policies. Global ACL's provides access control to IPv4/IPv6 traffic on all
interfaces except for internal interfaces such as Loopback, identity,
Internal-Control, Internal-Data, etc only in the ingress/input direction.
They do not support control-plane or per-user-override features. The order
of processing ACL's is given below.

 

Order - 

1. interface ACL's 

2. global ACL's

3. default glabal ACL rule (deny ip any any)

 

Interface ACL rules has a priority of 13 in the ASP table.

 

Global ACLs has a priority of 12 in the ASP table. (Higher the value more
the priority and higher priority is processed first, hence interface ACL's
are processed before Global ACL entries). 

 

It is very important to understand that the "implicit" deny ip any any of
the global ACL has a priority of 11 in the ASP table. This means that once a
global ACL is applied, the implicit deny ip any any rule is removed from the
interface rule and added to the end of the global rule automatically.

 

 

Samarth Chidanand

Sr Instructor / Developer - IPexpert

CCIE #18535 (R&S, Security)

CCSI #34585

 

 

 

From: Daljeet SinGH [mailto:[email protected]] 
Sent: Friday, April 26, 2013 10:49 AM
To: Samarth Chidanand
Cc: Mike Rojas; [email protected]
Subject: Re: [OSL | CCIE_Security] Workbook1 Task 12

 

But the Q is ,

as mentioned, there is already  inbound ACL on outside interface which will
be processed 1st, ?

 

On Fri, Apr 26, 2013 at 10:20 AM, Samarth Chidanand <[email protected]>
wrote:

Hi Mike,

 

See the answer below from the DSG. It's states use global ACL's, implies
more than one ACL.

 

 

 

 

Task 12: Manual static identity NAT on ASA-3

*       Create a loopback on R2 with an IP address of 222.222.222.222/32.
Configure static identity NAT such that only outside users can ping that IP
address. Use global ACLs to allow access.
*       Advertise the new loopback into RIPv2 on R2 and create appropriate
static routes on R4 and R5.

 

Task-12:Solutions

Step 1:  Configure Loopback on R2 and advertise into RIP.

int lo222

ip add 222.222.222.222 255.255.255.255

router rip

network 222.222.222.0

 

Step 2:  Configure Static routes on R4 and R5.

 

R5

ip route 222.222.222.222 255.255.255.255 100.100.35.105

 

R4

ip route 222.222.222.222 255.255.255.255 200.100.34.104

 

Step 3:  Configure objects on ASA3

 

object network R2_Loop222

host 222.222.222.222

 

 

Step 4:  Configure Manual identity NAT on ASA3

 

nat (dmz1,outside-1) source static R2_Loop222 R2_Loop222

 

nat (dmz1,outside-2) source static R2_Loop222 R2_Loop222

 

Step 5:  Configure global ACL's

 

access-list GLOBAL permit ip any object R2_Loop222

access-list GLOBAL permit ip object R2_Loop222 any

 

Verification

 

Step 1: Verify Manual NAT entries (Section-1). Entry 5 and 6 of section 1.

 

Manual NAT Policies (Section 1)

<SNIP>

5 (dmz1) to (Outside-1) source static R2_Loop222 R2_Loop222

    translate_hits = 0, untranslate_hits = 0

    Source - Origin: 222.222.222.222/32, Translated: 222.222.222.222/32

6 (dmz1) to (Outside-2) source static R2_Loop222 R2_Loop222

    translate_hits = 0, untranslate_hits = 0

    Source - Origin: 222.222.222.222/32, Translated: 222.222.222.222/32

<SNIP>

 

 

Step 2: Telnet from Lo222 to R4 and R5 and perform basic ping tests.

 

R2#telnet 45.45.45.4 /source-interface lo222

Trying 45.45.45.4 ... Open

 

R4#sh users

    Line       User       Host(s)              Idle       Location

   0 con 0                idle                 00:04:58

*514 vty 0                idle                 00:00:00 222.222.222.222

 

  Interface    User               Mode         Idle     Peer Address

 

R4#exit

 

[Connection to 45.45.45.4 closed by foreign host]

R2#ping 4.4.4.4 so lo 222

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:

Packet sent with a source address of 222.222.222.222

!!!!!

 

R2#ping 45.45.45.5 so lo 222

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 45.45.45.5, timeout is 2 seconds:

Packet sent with a source address of 222.222.222.222

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

 

 

 

 

R2#telnet 100.100.35.5 /source-interface lo222

Trying 100.100.35.5 ... Open

 

 

R5#show users

    Line       User       Host(s)              Idle       Location

   0 con 0                idle                 00:04:00

*514 vty 0                idle                 00:00:00 222.222.222.222

 

  Interface    User               Mode         Idle     Peer Address

 

R5#ping 222.222.222.222

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 222.222.222.222, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

R5#exit

 

[Connection to 100.100.35.5 closed by foreign host]

R2#

 

 

 

From: [email protected]
[mailto:[email protected]] On Behalf Of Mike Rojas
Sent: Friday, April 26, 2013 7:27 AM
To: [email protected]
Subject: [OSL | CCIE_Security] Workbook1 Task 12

 

Hi, 

This task says that you need to allow the traffic from the outside to the
loopback 222.222.222.222/32 on R2. The problem comes when it says that I
need to allow this using the Global ACL. There was already a Global ACL
configured but also, there are 2 access list on ASA3 used to allow traffic
inbound from outside at a previous task. 

The problem is that even if I allow that traffic on the global ACL, it is
not going to work, as the interface ACL is processed first than the Global
ACL. 

Is there something that I am doing wrong? 

Another question that comes up is that, for every object that needed to 2
NATs for both outside interfaces, I created the Object and then another
object with the same host and created the NAT there. Just checking if that
is correct. 

Finally, on a task I read, you can re-used the object for the Access
list....well, I reused every Object that I could :P so I dont know if
previous that task, I needed to create a new object for the ACLs. 

Mike. 


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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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