The trouble is Tom, if the Exchange team say not supported (exactly what this means I am not totally sure) and then one of my customers goes to PSS who says our ISA/Exchange deployment isn't supported, this puts us in a very difficult position as an MS solution provider who designed the solution... 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> ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: 11 January 2007 03:38 To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks Actually, an Internet facing host should NEVER be placed in the same security zone as non-Internet facing hosts. Since the CAS is an Internet facing host, it should be placed in a separate security zone, such as an authenticated access DMZ. The Exchange guys horks another green one with their doltish recommendations for the CAS -- no doubt due to their abject lack of understanding of the heterogeneity of "DMZs". Also, someone in this thread mixed up domain segmentation with network physical and logical segmentation -- a common N00b error, since there is no pre-defined relationship between the two. I would never put the CAS on my non-Internet facing host zone, no matter what the boneheads on the Exchange Team "think" -- heck, they're still putting the ISA Firewall between two "firewalls" in their docs. Those guys are the last ones I'd look to for guidance in network security (OK, Syphco guys are *the* last, but the Exchange guys and barely in front of them. Tom 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 7:13 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks Don't care; doesn't matter, misquoted. "Desirable" meaning "everyone wants to do it". Publishing RPC (MAPI) traffic is completely different from splitting your domain membership across the firewall. There is *no* good reason to do this. From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Jones Sent: Wednesday, January 10, 2007 4:30 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks Think you guys have completely misunderstood me, or I am amazed at your responses. We are not talking about ANY firewall here, we are talking about ISA...one of the key advantages of ISA is that you can create perimeter networks even for domain members as ISA can perform RPC and other app filtering. Hence you can move domain members that represent more of a security risk away from other domain member servers. Based upon your answers, you must all be in disagreement then with the models proposed by Tom for Exchange and network services protection???? http://www.isaserver.org/articles/2004multidmzp1.html http://www.isaserver.org/tutorials/Configure-ISA-2004-Network-Services-S egment-Perimeter-Firewall-Part1.html If so, I am very surprised. I posted here in August with a least privilege model for Exchange security which placed Exchange FE's, BE's and DC's into ISA perimeter networks and got good feedback - what the hell is going on???? Jim's quote "Ah, yes. While this is a desirable design, it's also a very difficult one." Steve's quote "Hat's off to you for being committed to deploying security-in-depth with least-privilege and not acquiescing to the "whatever works" mentality. I know it's a hard thing to deploy and support. While I have a similar topology, I only separate the clients from the servers with an infrastructure ISA box- not the BE's from the DC's; they're on the same "protected" network." Totally confused guys :-( ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Steve Moffat Sent: 10 January 2007 23:08 To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks That's what I said........ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison Sent: Wednesday, January 10, 2007 7:04 PM To: isapros@xxxxxxxxxxxxx; isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA, Exchange 2007 and Perimeter Networks 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> ________________________________ 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> 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+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.