Sounds like the dorks are getting to you -- that's how I feel when I start the day fielding questions from "hork mode" installs :\ Thomas W Shinder, M.D. Site: www.isaserver.org <http://www.isaserver.org/> Blog: http://blogs.isaserver.org/shinder Book: http://tinyurl.com/3xqb7 <http://tinyurl.com/3xqb7> MVP -- ISA Firewalls ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison Sent: Wednesday, January 10, 2007 8:08 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks True enough, but in the typical "DMZ" deployment, ISA merely sits "beside"; not "before" the published service, and thus protects it very little or not at all. This is the basic flaw in this design (as I've seen it so far). ..or maybe I'm just jaded from having to deal with all the "ISA isn't a firewall" d0rks5 day in and day out... From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: Wednesday, January 10, 2007 8:04 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks If the host is in the same domain, traffic between the domain member in the DMZ segment is limited to only the required traffic, not all traffic. This is least priv. Since SMTP, NNTP, IRC, H.323, SIP, etc., etc., aren't allowed from that segment to the other, we've locked out those exploits. Plus, we have a device in the path between the two security zones that is logging these attempts at illegitmate traffic and can provide information for further analysis. If you have an unincumbered path between the Internet facing host (which has a much larger "attacker surface") than the non-Internet facing host, then you're violating least priv and asking for problems you needent have. Thomas W Shinder, M.D. Site: www.isaserver.org <http://www.isaserver.org/> Blog: http://blogs.isaserver.org/shinder Book: http://tinyurl.com/3xqb7 <http://tinyurl.com/3xqb7> MVP -- ISA Firewalls ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison Sent: Wednesday, January 10, 2007 7:52 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks What's the diff between allowing domain traffic to the same DC you're trying to protect? The 1d10t cry of "what if it gets compromised?" is the core issue in this question. A host belonging to a separate domain is one thing; a member of the internal domain is quite another. From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: Wednesday, January 10, 2007 7:45 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks What's wrong with that? There is granularity of security zone definitions and membership, even within a domain. Just like what we've done with the FE Exchange Server, there's no qualitative or quanitative differences here that I can tell. Thomas W Shinder, M.D. Site: www.isaserver.org <http://www.isaserver.org/> Blog: http://blogs.isaserver.org/shinder Book: http://tinyurl.com/3xqb7 <http://tinyurl.com/3xqb7> MVP -- ISA Firewalls ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison Sent: Wednesday, January 10, 2007 7:11 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks 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] 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] 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&q=cas+dmz+i sa&rnum=2&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 All mail to and from this domain is GFI-scanned. All mail to and from this domain is GFI-scanned. All mail to and from this domain is GFI-scanned. All mail to and from this domain is GFI-scanned.