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Netrinc
PostPosted: Tue May 08, 2012 4:41 pm 
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Quick question here, I would like to implement a zone based firewall on my ASA5510. Is ZBF possible on ASA? or is it strictly for routers? I know we've implementd ZBF using Sonicwall firewalls before. A little confused here as to why my ASA doesnt have the right commands.

Maybe my version of ASA software is too old? It's 8.2 if i remember right.
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Vito_Corleone
PostPosted: Tue May 08, 2012 7:12 pm 
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ASAs run a sort of "zone-based firewall" by default. You configure interfaces (zones) and allow traffic into or out of them. It's not the same syntax, but it's a similar concept.

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zerojunkie
PostPosted: Tue May 08, 2012 7:26 pm 
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Unfortunately, iirc, the security-level business goes out the window once you apply an ACL to the interface. That's not the case with most other ZBFs I've tried.
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Vito_Corleone
PostPosted: Tue May 08, 2012 7:39 pm 
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zerojunkie wrote:
Unfortunately, iirc, the security-level business goes out the window once you apply an ACL to the interface. That's not the case with most other ZBFs I've tried.


Explain. I haven't used ZBF much at all, but I don't see how you could add an access rule and still have trust levels matter. Would you want a permit (or deny) ip any to be overridden by a default lower to higher/higher to lower rule?

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zerojunkie
PostPosted: Tue May 08, 2012 8:42 pm 
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Vito_Corleone wrote:
Explain. I haven't used ZBF much at all, but I don't see how you could add an access rule and still have trust levels matter. Would you want a permit (or deny) ip any to be overridden by a default lower to higher/higher to lower rule?


Best I can do is an example. If I have a guest, inside, and a DMZ network going through a firewall to the internet. On the ASA if I wanted to expose some DMZ hosts to the guest network my rule set for that interface would go allow/dmz, deny/inside then allow/any. I shouldn't have to put that deny/inside since those two interfaces have differing security-levels, but I do since that doesn't matter once an access-group gets applied. With a real ZBF, I should be able to specify access to the DMZ hosts and let the differing zones take care of disallowing traffic between the guest and inside interfaces.
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Vito_Corleone
PostPosted: Tue May 08, 2012 9:29 pm 
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I can see that if you're tying zone pairs together, which might be what you're trying to say - that the ASA lacks that ZNF functionality? But, with the architecture of ASA policy, I wouldn't really want it to work any other way.

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zerojunkie
PostPosted: Wed May 09, 2012 10:17 am 
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Vito_Corleone wrote:
I can see that if you're tying zone pairs together, which might be what you're trying to say - that the ASA lacks that ZNF functionality? But, with the architecture of ASA policy, I wouldn't really want it to work any other way.


Kinda. I mean, you can put two interfaces in the same "zone" and allow traffic between them so long as you don't have an ACL applied. I'm just lamenting the fact that if you want more granular control in the form of ACLs AND you still want the zone-like behavior you can't have it in the ASA platform. I do agree that the way the policy is designed it'd require a pretty drastic departure to include that behavior. Just seems like IOS gets all the cool security features (ZBF, DMVPN, etc...)while ASA is stuck being a firewall with a feature-set from the early-to-mid 00's.
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ristau5741
PostPosted: Wed May 09, 2012 11:25 am 
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similar to ZBF where FA0/1 is security 50 and fa0/2 is secuirty 50
same-security-traffic permit intra-interface
would allow communication between the two interfaces
aka ZBF

no ?

Code:
same-security-traffic

To permit communication between interfaces with equal security levels, or to allow traffic to enter and exit the same interface, use the same-security-traffic command in global configuration mode. To disable the same-security traffic, use the no form of this command.

same-security-traffic permit {inter-interface | intra-interface}

no same-security-traffic permit {inter-interface | intra-interface}
Syntax Description

inter-interface - Permits communication between different interfaces that have the same security level.

intra-interface - Permits communication in and out of the same interface.

Defaults
This command is disabled by default.

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Vito_Corleone
PostPosted: Wed May 09, 2012 11:53 am 
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zerojunkie wrote:
Vito_Corleone wrote:
I can see that if you're tying zone pairs together, which might be what you're trying to say - that the ASA lacks that ZNF functionality? But, with the architecture of ASA policy, I wouldn't really want it to work any other way.


Kinda. I mean, you can put two interfaces in the same "zone" and allow traffic between them so long as you don't have an ACL applied. I'm just lamenting the fact that if you want more granular control in the form of ACLs AND you still want the zone-like behavior you can't have it in the ASA platform. I do agree that the way the policy is designed it'd require a pretty drastic departure to include that behavior. Just seems like IOS gets all the cool security features (ZBF, DMVPN, etc...)while ASA is stuck being a firewall with a feature-set from the early-to-mid 00's.


I don't care about ZBF or DMVPN (this one especially as it's primarily routing) on the ASA. I want the new stuff, like CX. I want a firewall that can get rid of Websense, Packet Shapers, and do a lot of solid reporting on box (sounds remarkably like Palo Alto...).

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Netrinc
PostPosted: Wed May 09, 2012 1:07 pm 
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thanks guys

for this particular design it'd simplify my life and configuration to be able to lump many interfaces into only a couple zones and zone-pairs and not deal with so many ACLs.
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ristau5741
PostPosted: Wed May 09, 2012 2:49 pm 
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Netrinc wrote:
thanks guys

for this particular design it'd simplify my life and configuration to be able to lump many interfaces into only a couple zones and zone-pairs and not deal with so many ACLs.



use object groups ?

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Axis
PostPosted: Thu May 10, 2012 10:47 am 
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Vito_Corleone wrote:
zerojunkie wrote:
Unfortunately, iirc, the security-level business goes out the window once you apply an ACL to the interface. That's not the case with most other ZBFs I've tried.


Explain. I haven't used ZBF much at all, but I don't see how you could add an access rule and still have trust levels matter. Would you want a permit (or deny) ip any to be overridden by a default lower to higher/higher to lower rule?



Funny enough I came across this type of discussion in the cisco forms the other day where some guy was saying the complete opposite...I was like wtf? :shock: Granted it was from '10 and had popped up in a search I was doing

Quote:
Re: ASA / Same-security interface filtering with ACLs
Hello,

The same security traffic will override any ACL that you have apply on the interfaces with the same security. If you take a look at the ASDM says "Permit traffic to flow between same security interfaces". No ACL can override this rule.

Hope it helps.

Mike


He then goes on to say

Quote:
Hello,

Also to back me up over here, you can find the information here

"You can allow traffic to flow freely between all same security interfaces without access lists"

http://www.cisco.com/en/US/docs/securit ... #wp1289167

Since the same security traffic is checked prior an ACL, if this command is present, all the traffic will be allowed. If you want to do filtering, I would suggest you to take out the command and put the ACL's in all of the interfaces.

Cheers

Mike

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