Kingsley,

 

The purpose of using a static mroute is to rectify RPF failures when your
multicast feed is coming from a different direction than the IP routing
table states. I.E. your routing table states to get to 1.1.1.1 via DMZ
interface but you are receiving a multicast feed on interface inside from
1.1.1.1.  Using the static mroute states I know I need to get to 1.1.1.1 for
IP routing via DMZ but it is OK if I receive multicast feeds via my inside
interface sourced from 1.1.1.1.

 

You can have an interface on the firewall join a group for testing but you
shouldn't have the firewall join the group permanently unless it needs to
listen to the feed.  Otherwise you are just wasting resources.  Which in the
case of KEK the firewall is not participating so you are wasting resources. 

 

I will get back with you tomorrow morning with a working configuration based
on best practices to confirm what I stated below.

 

Regards,

 

Tyson Scott - CCIE #13513 R&S, Security, and SP

Technical Instructor - IPexpert, Inc.

Mailto: [email protected]

Telephone: +1.810.326.1444, ext. 208

Live Assistance, Please visit: www.ipexpert.com/chat

eFax: +1.810.454.0130

 

IPexpert is a premier provider of Classroom and Self-Study Cisco CCNA (R&S,
Voice & Security), CCNP, CCVP, CCSP and CCIE (R&S, Voice, Security & Service
Provider) Certification Training with locations throughout the United
States, Europe and Australia. Be sure to check out our online communities at
www.ipexpert.com/communities and our public website at www.ipexpert.com

 

From: Kingsley Charles [mailto:[email protected]] 
Sent: Sunday, December 06, 2009 11:46 PM
To: Tyson Scott
Cc: Mohamed Shams; [email protected]
Subject: Re: [OSL | CCIE_Security] GETVPN multicast rekey

 

Hi Tyson/Mohamed

 

I think, the following should enough right?

 

 

GM ----------------- inside ASA outside -------------------- KS

 

 

multicasting routing 

 

mroute 0 0 <next hop>

 

interface g0/0

nameif outside 

ip igmp join <multicast address>

 

interface g0/1

nameif inside

igmp forward interface outside

 

The GM gets the multicast address from the KS and starts listening for it.
Since ASA in between, we can configure for SMR.  The ASA will join the
mutlicast group and start forwarding the multicast request.

 

 

 

Since the mutlicast request is from inside, no punching hole is required
with ACL to permit the muilticast inside.

 

Please correct me, if I am wrong.

 

 

With regards

Kings

On Mon, Dec 7, 2009 at 9:01 AM, Tyson Scott <[email protected]> wrote:

Mohamed,

 

Again you are still going to be enabling PIM but you would then need to
allow the multicast feed thru the firewall.

 

access-list OUT_TO_IN permit udp host <key-server> host <Multicast-group> eq
<specific-port-numbers if you know them>

 

(At least I assume you would need the ACL for the multicast feeds.  I
haven't actually run multicast from the outside to inside yet.  Will test it
tomorrow and respond if I am wrong.)

 

When I used to be in charge of Security, working in real world, we always
had to run GRE tunnels thru the PIX with static mroute's to pass the
multicast traffic.  Prior to 7.0 the PIX didn't support multicast at all.

 

You should try the new labs and see if helps you for your problem.  We
actually spent a great deal of time explaining multicast and how it
functions so I hope it is helpful.  (At least enough for what you would need
to know for the Security Lab.) It definitely doesn't go into the detail of
our R&S and SP books as there is a lot more to know.

 

Regards,

 

Tyson Scott - CCIE #13513 R&S, Security, and SP

Technical Instructor - IPexpert, Inc.

Mailto: [email protected]

Telephone: +1.810.326.1444, ext. 208

Live Assistance, Please visit: www.ipexpert.com/chat

eFax: +1.810.454.0130

 

 

From: Mohamed Shams [mailto:[email protected]] 
Sent: Sunday, December 06, 2009 3:43 AM
To: [email protected]; Tyson Scott 


Subject: RE: [OSL | CCIE_Security] GETVPN multicast rekey

 


Tyson 

thank you for your fast response ,

only PIM needs to be enabled ? 
and what if the KS is in the outside zone and the GM's in the inside , what
will be the outside acl in this case ?



Best Regards,

Mohamed Shams 

Senior Network Security Engineer

Mob. +971505547296 / +971559814508 (UAE)
Mob. +20102340178 (Egypt)



--- On Sun, 12/6/09, Tyson Scott <[email protected]> wrote:


From: Tyson Scott <[email protected]>
Subject: RE: [OSL | CCIE_Security] GETVPN multicast rekey
To: "'Mohamed Shams'" <[email protected]>,
[email protected]
Date: Sunday, December 6, 2009, 10:21 AM

Mohamed,

 

It depends.  Are you running multi context or single context?  Single
context you need to enable PIM on the firewall as well as all the rest of
the devices that will be communicating with it.

 

Multi context routed mode doesn't support multicast so you need to provide a
workaround.

 

I actually put this in Lab17 and Lab20 due to the recent comment by Yusuf on
Cisco's Cert Forum that you guys should know basic multicast because it was
the only thing that I could think that would require you to use multicast in
the lab.  Maybe something would require it as well but I can't think of
anything else.

 

Regards,

 

Tyson Scott - CCIE #13513 R&S, Security, and SP

Technical Instructor - IPexpert, Inc.

Mailto: [email protected]

Telephone: +1.810.326.1444, ext. 208

Live Assistance, Please visit: www.ipexpert.com/chat

eFax: +1.810.454.0130

 

IPexpert is a premier provider of Classroom and Self-Study Cisco CCNA (R&S,
Voice & Security), CCNP, CCVP, CCSP and CCIE (R&S, Voice, Security & Service
Provider) Certification Training with locations throughout the United
States, Europe and Australia. Be sure to check out our online communities at
www.ipexpert.com/communities and our public website at www.ipexpert.com
<http://www.ipexpert.com/> 

 

From: [email protected]
[mailto:[email protected]] On Behalf Of Mohamed
Shams
Sent: Sunday, December 06, 2009 2:57 AM
To: [email protected]
Subject: [OSL | CCIE_Security] GETVPN multicast rekey

 



Hi all

I have an ASA firewall between the key server (KS) and its group members
(GM) , where the KS in the inside zone and the GMs are in the  outside zone
, GMs registered successfully with the KS and traffic is encrypted/decrypted
without any problems , but the only problem that the GM's don't receive the
rekey messages provided that the rekey is multicast 

my question is what should be done on the firewall to allow multicast
rekeying .

thank you 

Best Regards,

Mohamed Shams 

Senior Network Security Engineer

Mob. +971505547296 / +971559814508 (UAE)
Mob. +20102340178 (Egypt)

 

 


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