Hey all,

Slowly but surely I'm managing to understand ZBF and its practicality in the 
real world, but I had a few questions that maybe you guys can help me with.  
Hopefully not too off-topic :).


1.       How does ZBF handle services that are "terminated" on the router but 
theoretically are more transit traffic?  For instance - Static NAT, Voice 
MTPs/Transcoders, H323/MGCP/SCCP signaling, Analog/TDM to IP conversion, etc.  
Do we need to define a 'self-zone' policy if we wish to protect who can/can't 
access these resources of the router?  I know Tyson suggests using CoPP (or 
even an appropriately placed ACL) to protect the router in lieu of a self-zone 
policy, but what about in the above scenario?  I've had mixed results in the 
labs I've tested this with, but was wondering what the appropriate approach 
should be?  Especially since some of these services require inspection (such as 
with RTP) in order to work correctly through a Firewall.  I can't find a 
clear-cut answer on Cisco's website and all Configuration Guides suggest 
building a self-zone policy.  This seems to come up a lot with a "branch" 
router scenario in which there are a lot of integrated services in a single box.

2.       What is the general consensus on RFC1918/2824/etc. ingress filtering 
using ZBF (from the perspective of securing both transit traffic, and traffic 
destined to the router itself)?  Should this now be handled through ZBF and 
CoPP?  ZBF and self-zone policy?  An inbound ACL?  I only ask because it seems 
logical that ZBF and CoPP are how Cisco would like to approach the solution... 
though an ACL would easily satisfy the criteria with little to no effort.  It 
seems overly complicated to use ZBF and CoPP, but maybe I'm missing the bigger 
picture?

Thanks for the help all!

Aaron T. Rohyans
Senior Network Engineer
CCIE #21945
DPSciences Corporation
7400 N. Shadeland Ave., Suite 245
Indianapolis, IN 46250
Office:  (317) 348-0099
Fax:   (317) 849-7134
[email protected]<mailto:[email protected]>
http://www.dpsciences.com/
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as a small child before he invents the virus..."
"There are 10 kinds of people in this world... those who can read binary, and 
those who can't"

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