[isapros] Re: ISA, Exchange 2007 and Perimeter Networks

  • From: "Steve Moffat" <steve@xxxxxxxxxx>
  • To: <isapros@xxxxxxxxxxxxx>
  • Date: Thu, 11 Jan 2007 18:17:15 -0400

No they are not!!!

 

From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx]
On Behalf Of Greg Mulholland
Sent: Thursday, January 11, 2007 6:11 PM
To: isapros@xxxxxxxxxxxxx
Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks

 

Oh hell no.. please dont! they are hideous

        ----- Original Message ----- 

        From: Thor (Hammer of God) <mailto:thor@xxxxxxxxxxxxxxx>  

        To: isapros@xxxxxxxxxxxxx 

        Sent: Friday, January 12, 2007 6:41 AM

        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks

         

        Hey Gerald- your last couple of posts all came in as base64
encoded text.  Was that on purpose?  Just didn't want to approve the
post if you were sending out naked pictures of Steve or something...
        
        t
        
        
        On 1/11/07 9:09 AM, "Gerald G. Young" <g.young@xxxxxxxx> spoketh
to all:

        I always saw it as "initiation by fire". J
        
        
        Cordially yours,
        Jerry G. Young II
        Product Engineer - Senior
        Platform Engineering, Enterprise Hosting
        NTT America, an NTT Communications Company
         
        22451 Shaw Rd.
        Sterling, VA 20166
         
        Office: 571-434-1319
        Fax: 703-333-6749
        Email: g.young@xxxxxxxx
         
        
        From: isapros-bounce@xxxxxxxxxxxxx
[mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thor (Hammer of God)
        Sent: Thursday, January 11, 2007 11:46 AM
        To: isapros@xxxxxxxxxxxxx
        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks
        
        "Overly poky."  Kind of hard for me to argue with that one :-p
        
        t
        
        
        On 1/11/07 7:09 AM, "Amy Babinchak"
<amy@xxxxxxxxxxxxxxxxxxxxxxxxxx> spoketh to all:
        Jason don't get discouraged. The changes in Exchange are
monumental so there are bound to be disagreements and changes of opinion
on how to best secure it. The concept of an authenticated access DMZ in
a separate security zone allowing only a very minimal set of protocols
is a completely foreign concept to 99% of firewall admins out there.
That fact you are even thinking about this stuff put you in an elite
class. The rest are still poking holes and setting up VLANs. 
         
        Tom, Thor and Jim can be a bit clubby and a little overly poky
to new comers. It's a twitch they developed after participating on the
ISA server mailing list. It got worse when they decided to join a
general purpose SBS list. I'm not sure that they'll ever completely
recover.  
         
        
        Amy 
         
        
         
          

        
________________________________


        
        From: isapros-bounce@xxxxxxxxxxxxx
[mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Jones
        Sent: Thursday, January 11, 2007 5:47 AM
        To: isapros@xxxxxxxxxxxxx
        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks
        
        Wish I had never asked now...sometimes, some of you guys really
don't make it easy for new people to try express their views and pose
questions for comment without being slapped down. One minute I am being
labelled as an "idiot" for my comments/views, the next minute someone
else who says the same thing as me is now right and not challenged. What
gives?  
        
        I know many of you guys don't know me from Adam, but kinda
unfair to just assume I know jack about ISA and secure network design
just because I'm not "part of the club".
        
        
        Anyhow, thanks to Tim and Tom for seeming to share my
disappointment with the decision made by the Exchange 2007 team...I
think I need to try and find out how "official" their lack of support
with 2k7 is going to be before I can continue recommending the least
privilege model I have been using for Exchange 2003.

        
________________________________


        
        From: isapros-bounce@xxxxxxxxxxxxx
[mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison
        Sent: 11 January 2007 04:30
        To: isapros@xxxxxxxxxxxxx
        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks
        ..maybe I'm just tired...
        I spent two hours trying to get home tonight and I'm clearly not
in my mind (right or otherwise).
        Forget I wrote and we'll start over tomorrow...
        
        
        From: isapros-bounce@xxxxxxxxxxxxx
[mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thor (Hammer of God)
        Sent: Wednesday, January 10, 2007 8:18 PM
        To: isapros@xxxxxxxxxxxxx
        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks
        
        That's exactly what I'm talking about.  And precisely the
configuration I deploy:
        
        My FE is in the authenticated segment of the DMZ - and a member
of my internal domain; however, the "recommended protocols" the Exchange
group recommends are not necessary- and thus, Steve's contention that
"CIFS and all that other stuff... Might as well just be internal" I
reject.  I only allow Kerberos-Sec, LDAP, LDAP GC, Ping and DNS only
from my FE to the internal DC's.  And only HTTP to the BE's.  
        
        Even if the other prots WERE required, it would still be far
smarter to deploy the FE in the authenticated DMZ with limited access
than to just give full stack access to the ENTIRE internal network.
This is a deployment of a services made available (initially) to a
global, anonymous, untrusted network. 
        
        Maybe I'm not properly articulating my point, but I have to say
I'm really surprised that we are having this conversation...
        
        t
        
        
        On 1/10/07 7:10 PM, "Jim Harrison" <Jim@xxxxxxxxxxxx> spoketh to
all:
        C'mon, Tim; I know what your deployment recommendations are;
this isn't it.
        He wants to extend his domain via "remote membership"; not
create a separate domain.
         
        
        From: isapros-bounce@xxxxxxxxxxxxx
[mailto:isapros-bounce@xxxxxxxxxxxxx]
<mailto:isapros-bounce@xxxxxxxxxxxxx%5d>
<mailto:isapros-bounce@xxxxxxxxxxxxx%5d>  On Behalf Of Thor (Hammer of
God)
        Sent: Wednesday, January 10, 2007 4:26 PM
        To: isapros@xxxxxxxxxxxxx
        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks
         
        Because it's safer that way, that's why... That's what an
authenticated access DMZ perimeter is for- with a CAS server that
presents logon services to any Internet user, I would (and, in fact,
require) that the server be in a least-privileged authenticated access
perimeter network that limits that servers communications to the minimum
required for required functionality - and only to the hosts it needs to
talk to.
        
        Let's say there is a front-end implementation issue or coding
vulnerability: the CAS on the internal network would allow unfettered,
full-stack access to the internal network.  A CAS in a perimeter DMZ
would mitigate potential exposure in the event of a 0day or
configuration issue. 
        
        "Safer on the internal network" is a complete misnomer when it
comes to servers presenting services to an untrusted network. 
        
        t
        
        
        On 1/10/07 3:04 PM, "Jim Harrison" <Jim@xxxxxxxxxxxx> spoketh to
all:
        Why would you want to place a member of your internal domain in
your DMZ, fer chrissakes?!?
        Hosting any domain member in the DMZ is a difficult proposition;
especially where NAT is the order of the day.
        You can either use a network shotgun at your firewall or attempt
to use your facvorite VPN tunnel across the firewall to the domain.
        
        Jim 

        
________________________________


        
        
        From: isapros-bounce@xxxxxxxxxxxxx on behalf of Jason Jones
        Sent: Wed 1/10/2007 2:35 PM
        To: isapros@xxxxxxxxxxxxx
        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks
        
        From what I can gather, the new CAS role now uses RPC to
communicate with the back-end (not sure of new name!) servers so I am
guessing that this is an "RPC isn't safe across firewalls" type stance.
Which I guess for a PIX, is a pretty true statement.
        
        Just think how much safer the world will be when firewalls can
understand dynamic protocols like RPC...maybe one day firewalls will
even be able to understand and filter based upon RPC interface...maybe
one day... :-D ;-)
        
        Shame the Exchange team can't see how much ISA changes the
traditional approach to DMZ thinking...kinda makes you think that both
teams work for a different company :-(
        Jason Jones | Silversands Limited | Desk: +44 (0)1202 360489 |
Mobile: +44 (0)7971 500312 | Fax: +44 (0)1202 360900 | Email:
jason.jones@xxxxxxxxxxxxxxxxx <mailto:jason.jones@xxxxxxxxxxxxxxxxx>
<mailto:jason.jones@xxxxxxxxxxxxxxxxx>  
        
          

        
________________________________


        
        From: isapros-bounce@xxxxxxxxxxxxx
[mailto:isapros-bounce@xxxxxxxxxxxxx]
<mailto:isapros-bounce@xxxxxxxxxxxxx%5d>
<mailto:isapros-bounce@xxxxxxxxxxxxx%5d>  On Behalf Of Greg Mulholland
        Sent: 10 January 2007 22:07
        To: isapros@xxxxxxxxxxxxx
        Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks
        
        I seriously hope that they have take different paths and these
are not limitations on the software or it is going to mean a nice little
redesign and break from custom..
        
        Greg
        ----- Original Message ----- 
        From: Jason Jones <mailto:Jason.Jones@xxxxxxxxxxxxxxxxx>
<mailto:Jason.Jones@xxxxxxxxxxxxxxxxx>   
        To: isapros@xxxxxxxxxxxxx 
        Sent: Thursday, January 11, 2007 8:25 AM
        Subject: [isapros] ISA, Exchange 2007 and Perimeter Networks
        
        
        Hi All, 
        
        I heard today from an Exchange MVP colleague that members of the
Exchange team (Scott Schnoll) are saying that they (Microsoft) do not
support placing the new Exchange 2007 Client Access Server (like the old
Exch2k3 FE role) role into a perimeter network. Has anyone else heard
the same? This sounds very similar to Exchange admins of old when they
didn't really understand modern application firewalls like ISA could do
- RPC filter anyone???
http://groups.google.co.uk/group/microsoft.public.exchange.design/browse
_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&q=cas+dmz+isa&rn
um=2&hl=en#4db165c21599cf9b
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&amp;q=cas+dmz+i
sa&amp;rnum=2&amp;hl=en#4db165c21599cf9b>
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&q=cas+dmz+isa&r
num=2&hl=en#4db165c21599cf9b>
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&amp;q=cas+dmz+i
sa&amp;rnum=2&amp;hl=en#4db165c21599cf9b>
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&q=cas+dmz+isa&r
num=2&hl=en#4db165c21599cf9b>
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&amp;q=cas+dmz+i
sa&amp;rnum=2&amp;hl=en#4db165c21599cf9b>
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&q=cas+dmz+isa&r
num=2&hl=en#4db165c21599cf9b>
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&amp;q=cas+dmz+i
sa&amp;rnum=2&amp;hl=en#4db165c21599cf9b>
<http://groups.google.co.uk/group/microsoft.public.exchange.design/brows
e_thread/thread/4ecab9cb8e50015e/4db165c21599cf9b?lnk=st&q=cas+dmz+isa&r
num=2&hl=en#4db165c21599cf9b>  
        
        I have just about managed to convince Exchange colleagues (and
customers) of the value of placing Exchange FE servers in a separate
security zone from BE servers, DC's etc and now I here this...
        
        Are the Exchange team confusing the old traditional DMZ's with
what ISA can achieve with perimeter networks? 
        
        From what I believe, it is good perimeter security practice to
place servers which are Internet accessible into different security
zones than servers that are purely internal. Therefore, the idea of
placing Exchange 2003 FE servers in an ISA auth access perimeter network
with Exchange 2003 BE servers on the internal network has always seemed
like a good approach. It also follows a good least privilege model. 
        
        Is this another example of the Exchange and ISA teams following
different paths???? 
        
        Please tell me that I am wrong and that I am not going to have
to start putting all Exchange roles, irrespective of security risk, on
the same network again!!!!
        
        Comments? 
        
        Cheers 
        
        JJ 

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