Which the client-side proxy would then probably block, as it is a non-standard port :-) :-) -----Original Message----- From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison Sent: 20 September 2007 14:48 To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs I see what you mean. Look at it this way - the benefit for a SRV record in this case is to specify a non-standard port if one is required. -----Original Message----- From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Jones Sent: Thursday, September 20, 2007 3:29 AM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs From what I can tell, OA looks for the A record first, this is the bit that seems silly...especially when combined with the issues of SRV and CERN proxies. Quote from KB: In this example, the Autodiscover service does the following when the client tries to contact the Autodiscover service: 1. Autodiscover posts to https://contoso.com/Autodiscover/Autodiscover.xml. This fails. 2. Autodiscover posts to https://autodiscover.contoso.com/Autodiscover/Autodiscover.xml. This fails. 3. Autodiscover performs the following redirect check: GET http://autodiscover.contoso.com/Autodiscover/Autodiscover.xml This fails. 4. Autodiscover uses DNS SRV lookup for _autodiscover._tcp.contoso.com, and then "mail.contoso.com" is returned. 5. Outlook asks permission from the user to continue with Autodiscover to post to https://mail.contoso.com/autodiscover/autodiscover.xml. 6. Autodiscover's POST request is successfully posted to https://mail.contoso.com/autodiscover/autodiscover.xml. The Outlook 2007 "Test E-Mail Auto Configuration" utility also follows the same sequence of doing A records first. JJ -----Original Message----- From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison Sent: 20 September 2007 01:03 To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs Actually, what I'm saying is that if OL 2003/7 is operating as a CERN proxy client, it performs absolutely no name queries at all; regardless of whether the name is listed as an A, SRV, TXT, CNAME, etc. record. This is the basic nature of a CERN proxy client; it sends a "gimme this, wouldya?" request without regard for how the endpoint might be resolved. Thus, OL will never communicate with a DNS server in this scenario. The egress proxy will seek an A record, since there is no way for the CERN proxy client to specify how the proxy should resolve the destination (it's just not part of the protocol). You're correct that you have to maintain A as well as SRV records if you intend to support CERN proxy as well as direct-connected clients. I'm not sure how "silly" this is, since CERN proxy mechanisms existed long before OL started using autodiscover. AFAIK, OL will seek the SRV record first, since this is much more informative than the A record. Jim -----Original Message----- From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Jones Sent: Tuesday, September 18, 2007 3:42 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs Hi Jim, So, in reality, we are saying that you can never be sure Outlook 2007 will work correctly with SRV records if you are unsure if the client will ever be working from behind a CERN proxy?? This seems a little silly as the SRV check is the last in the list, so therefore you will always need an A record for autodiscover.domain.com to cater to clients that *may* be behind a proxy. If this A record exists, surely Outlook will never actually use the SRV record (as it is only used if the A record cannot be found) and you still need ISA publishing and certs for autodiscover.domain.com to allow for "behind proxy" outlook clients... As we provide solution for customers, I cannot really afford to deploy a solution that may or may not work depending on whether the Outlook client is behind a proxy or not. So I feel forced to have to go with the A record method (reluctantly) to avoid potentially embarrassing questions when a CEO cannot get OA to work when at an internet café that uses a CERN proxy... Am I way off base here or does the logic seem wrong to you??? Cheers JJ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison Sent: 31 August 2007 15:00 To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs The problem is that many applications operating behind CERN, SOCKS or Socket proxies can't use SRV records. 1. CERN proxy clients *never* perform name resolution for themselves other than to determine if a host is local or remote. When it comes time to make the connection, OL (for instance), will simple send a "GET http://autodiscover.domain.tld/autodiscover.xml"; via its local CERN proxy. The proxy assumes that it should resolve "autodiscover.domain.tld" using an A record query and continues on that basis If all you build is a SRV record, this connection will fail. 2. SOCKS proxy clients *may* self-resolve names; it depends on the SOCKS version in use by the application and SOCKS proxy. For the record, ISA operates as SOCKS 4.3A, meaning that it is capable of performing name resolution on behalf of the client. If the application knows that it is speaking to a SOCKS4.3a proxy, it will make the connection request using the hostname. In this case, the proxy handles name resolution in the same way that a CERN proxy does. If the SOCKS proxy is operating as SOCKS4 or earlier and the application knows this, the application is required to perform its own name resolution. 3. Socket proxy (think FWC) clients will perform name resolution as if they had access to the 'Net. How this process is handled depends on how the client makes the name lookup request. If it (as OL does) makes a Winsock GetHostByname or GetAddrInfo call, they don't specify the type of record they want, and Winsock (and the Winsock LSP/BSP) will send it to the proxy as received. IOW, it's a rare case where a proxy-served client will even seek; much less receive the SRV record. Jim From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: Friday, August 31, 2007 6:42 AM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs Hi Jason, OK, that makes perfect sense and it's the scenario I'm testing today. One listener, one rule for Outlook Anywhere and one rule for Autodiscovery, correct? So I was right that you can't use the /AutoDiscover path that is included in the Outlook Anywhere rule since the Outlook Anywhere rule doesn't respond to the public name autodiscover.domain.com. The Outlook Autodiscover rule would respond to autodiscover.domain.com and forward to the /AutoDiscover path. The SRV record solution will solve ALL of this complexity because it will bypass the need for a second URL and second IP address and second certificate. However, its a hotfix that you have to call PSS to download and will be included with Office 2007 SP1. Thanks! 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 MVP -- Microsoft Firewalls (ISA) ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Jones Sent: Friday, August 31, 2007 8:15 AM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs Yep - one listener, two IPs, each IP assigned a different SSL cert. Not sure if the SRV record will negate the need for the autodiscover URL and hence allow us to get away with a single SSL cert - have to check this... From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: 31 August 2007 14:13 To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs Hi Jason, One Web listener, but two IP addresses are being used by the Web listener, correct? Thanks! 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 MVP -- Microsoft Firewalls (ISA) ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Jones Sent: Friday, August 31, 2007 6:50 AM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs Hi Tom, Managed to get this working today too, although I am using two individual certs on the same external web listener. The internal cert on Exchange is SAN'd up and ISA publishes everything to the internal cert common name irrespective of the public URL. The key to most of it working is defining correct URLs in Exchange where is defines "External URLs" for things like OOF, OAB, EWS etc. Now we have all exchange 2k7 services (and all the new funky stuff) working externally...had to do a lot of it by investigation and cobbling blog entries together, not ideal, but go there at last. We currently have it working without SRV records, but just waiting for the ISP to add these records to test if that is a better solution... Cheers JJ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: 31 August 2007 00:32 To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs I'd think that Jim might need to update his SAN article. The article implies that ISA doesn't support SANs on the Web listener, however I have a guy who has the autodiscover FQDN as a second SAN on the certificate bound to his Web listener and he's shown me strong evidence that it actually works, even though it shouldn't. I wish the Exchange or ISA UE teams could get it together to explain how to get autodiscovery working correctly and more importantly, show us how it works with and without DNS SRV records. It looks like once you have DNS SRV records, its a no brainer. 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 MVP -- Microsoft Firewalls (ISA) ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: Wednesday, August 29, 2007 2:38 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs Never mind :) I found it: http://support.microsoft.com/kb/940881 Thomas W Shinder, M.D. Site: www.isaserver.org <http://www.isaserver.org/> Blog: http://blogs.isaserver.org/shinder/ Book: http://tinyurl.com/3xqb7 MVP -- Microsoft Firewalls (ISA) ________________________________ From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Thomas W Shinder Sent: Wednesday, August 29, 2007 2:35 PM To: isapros@xxxxxxxxxxxxx Subject: [isapros] Re: ISA and SAN Certs OK, that's an interesting sentence in a KB OL update article. But there's no mention of this anywhere else on the ms.com site. In addition, how do we configure the SRV records? Service? Protocol? Priority? Weight? Port number? Host offering this service? cid:image001.jpg@01C7F522.ABDB5600 I try to read minds best as I can, but I'm flailing on this one :)) Thomas W Shinder, M.D. Site: www.isaserver.org Blog: http://blogs.isaserver.org/shinder/ Book: http://tinyurl.com/3xqb7 MVP -- Microsoft Firewalls (ISA) > -----Original Message----- > From: isapros-bounce@xxxxxxxxxxxxx > [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison > Sent: Wednesday, August 29, 2007 2:27 PM > To: isapros@xxxxxxxxxxxxx > Subject: [isapros] Re: ISA and SAN Certs > > DatzDeWun! O'curse it works in real life; I tested it. > > http://support.microsoft.com/kb/939184 > OL 2K7 seeks a "autodiscovery" SRV record first, and only if > that fails, > it'll seek the A record. This is based on the same domain suffix as > specified in the mail domain. > If your OL client is behind a CERN proxy (and it knows it), it can't > specify that the proxy should look up a SRV record for > autodiscover.sfx. > The proxy assumes that any CERN request will be for a "host" > and makes a > DNS query for an A record. > > OL 2K7 uses the SRV record to discover the host > > -----Original Message----- > From: isapros-bounce@xxxxxxxxxxxxx > [mailto:isapros-bounce@xxxxxxxxxxxxx] > On Behalf Of Thomas W Shinder > Sent: Wednesday, August 29, 2007 12:15 PM > To: isapros@xxxxxxxxxxxxx > Subject: [isapros] Re: ISA and SAN Certs > > BAM!!!! > > I think I get it. On the TO tab for the autodiscover.msfirewall.org, I > can still use owa.msfirewall.org since it resolves to the same IP > address as autodiscover.msfirewall.org on the internal network -- and > the path is going to /autodiscover, so that's cool. It's all making > sense on paper -- now to see if it works in real life :) > > BTW -- why do I need a SRV record for OL autodiscovery? I haven't seen > any documentation on that requirement on the Exchange side. > > Thanks! > Tom > > Thomas W Shinder, M.D. > Site: www.isaserver.org > Blog: http://blogs.isaserver.org/shinder/ > Book: http://tinyurl.com/3xqb7 > MVP -- Microsoft Firewalls (ISA) > > > > > -----Original Message----- > > From: isapros-bounce@xxxxxxxxxxxxx > > [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison > > Sent: Wednesday, August 29, 2007 2:09 PM > > To: isapros@xxxxxxxxxxxxx > > Subject: [isapros] Re: ISA and SAN Certs > > > > Yes; I'd forgotten about the OL client's "SAN problem". > > It amazed me how much noise the Exch folks make about the same > > limitation for ISA.. ..but I digress. > > > > "Web Publishing Rule that is publishing the > > autodiscover.msfirewall.org/autodiscover path must be > > configured on the > > TO tab to use autodiscover.msfirewall.org " - how do you > cone to that > > contusion? > > Why do you think you need to use "autodiscover" in the ISA rule > > published hostname? Use whatever works for ISA and let the > > client be as > > stupid as you want. > > > > -----Original Message----- > > From: isapros-bounce@xxxxxxxxxxxxx > > [mailto:isapros-bounce@xxxxxxxxxxxxx] > > On Behalf Of Thomas W Shinder > > Sent: Wednesday, August 29, 2007 12:05 PM > > To: isapros@xxxxxxxxxxxxx > > Subject: [isapros] Re: ISA and SAN Certs > > > > Hi Jim, > > > > CIL... > > > > Thomas W Shinder, M.D. > > Site: www.isaserver.org > > Blog: http://blogs.isaserver.org/shinder/ > > Book: http://tinyurl.com/3xqb7 > > MVP -- Microsoft Firewalls (ISA) > > > > > > > > > -----Original Message----- > > > From: isapros-bounce@xxxxxxxxxxxxx > > > [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison > > > Sent: Wednesday, August 29, 2007 1:49 PM > > > To: isapros@xxxxxxxxxxxxx > > > Subject: [isapros] Re: ISA and SAN Certs > > > > > > All good points, but really orthogonal to the question of how ISA > > > handles SAN certs. Actually, I wrote that because some folks were > > > whining about how ISA handled SAN certs in general. In > > fact, I tried > > > not to delve into the variant forms of self-inflicted ISA > manglement > > > pain that were filling other blogs. > > > > > > Q1 - Why do you need a second listener? Use your DNS to point > > > autodiscover to the same Exch listener. The public name is a > > > rule; not > > > a listener arttribute. > > > > TOM: We need a second listener because we can't have two > certificates > > with different common names listening on the same listener using the > > same IP address. OK, in ISA 2006 I *can* use multiple > > certificates using > > the same listener, but each of the certificates must be > assigned to a > > different IP address, so no big deal there -- so I create two > > different > > Web Publishing Rules -- one for owa.msfirewall.org and a second Web > > Publishing Rule for autodiscover.msfirewall.org. So far so > > good and SANs > > aren't even an issue. > > > > > Q2 - why does the external OL client give a rats bahootie > > > what's listed > > > in the cert used at the CAS? It never sees it. > > > > TOM: That's true and I didn't mean to imply that it did. The > > concern is > > that common name and the first SAN on the Web site > > certificate bound to > > the Client Access Server site is owa.msfirewall.org. The > second SAN is > > autodiscover.msfirewall.org > > > > > > > Q3 - why is the lack of the autodiscover.suffix public > name make the > > > /autodiscover path "useless"? "Incomplete" perhaps, but > > > hardly useless. > > > > TOM: Because the OWA publishing rule is listening for > > owa.msfirewall.org, NOT autodiscover.msfirewall.org. Since > > there are two > > certificates involved here, one with the common name > > owa.msfirewall.org > > and a second with autodiscover.msfirewall.org -- we have to use two > > different IP addresses, and owa.msfirewall.org is NOT going > to resolve > > to the same IP address as autodiscover.msfirewall.org. Thus, > > adding the > > /autodiscover path to the owa.msfirewall.org Web Publishing > Rule won't > > work and is extraneous. The /autodiscover path only applies to the > > autodiscover.msfirewall.org Web Publishing Rule. > > > > > > > > IOW, create your SRV and A records for autodiscover.suffix, add > > > "autodiscover.suffix" to the public names (ISA 2006 only) and > > > make sure > > > the cert used in the ISA web listener includes > > > "autodiscover.suffix" in > > > the SAN. > > > > Again, the issue isn't with the Web listeners, I have no > problem with > > that. The issue is with the connection between the ISA > > Firewall and the > > Client Access Server. The Web site certificate bound to the Client > > Access Server has a common name and a first SAN name of > > owa.msfirewall.org and a second SAN name of > > autodiscover.msfirewall.org. > > > > Given that, the Web Publishing Rule that is publishing the > > autodiscover.msfirewall.org/autodiscover path must be > > configured on the > > TO tab to use autodiscover.msfirewall.org -- HOWEVER, and > this is THE > > QUESTION -- with the ISA Firewall when establishing the SSL channel > > between itself and the Client Access Server, be able to use > the SECOND > > SAN on the Client Access Server Web site certificate to allow the > > connection? > > > > Make sense? > > > > > > > > > > Jim > > > > > > -----Original Message----- > > > From: isapros-bounce@xxxxxxxxxxxxx > > > [mailto:isapros-bounce@xxxxxxxxxxxxx] > > > On Behalf Of Thomas W Shinder > > > Sent: Wednesday, August 29, 2007 11:33 AM > > > To: isapros@xxxxxxxxxxxxx > > > Subject: [isapros] Re: ISA and SAN Certs > > > > > > This is a good step in understanding some of the issues, > > but I suspect > > > the major problems people are running into relates to > publishing the > > > autodisocvery site. You'll notice that when you run the Exchange > > > Publishing Wizard in ISA 2006 that is includes an > > /autodiscover path, > > > which is completely useless, since the client is looking for > > > autodiscover.domain.com/autodiscover and not the Client > > Access Server > > > Public Name, which would be something like owa.domain.com. > > > > > > OK, easy problem to solve, right? All we need to do is > > create a second > > > Web listener on a second IP address and configure it to listen for > > > public name autodiscover.company.com. HOWEVER, the Client Access > > > Server's common/subject name and first SAN is owa.company.com. The > > > second SAN is autodiscover.company.com. > > > > > > So, if we put on the TO tab autodiscover.company.com, will > > ISA 2006 be > > > able to "consume" the second SAN to support to the Outlook 2007 > > > autodiscovery service? > > > > > > Thanks! > > > Tom > > > > > > Thomas W Shinder, M.D. > > > Site: www.isaserver.org > > > Blog: http://blogs.isaserver.org/shinder/ > > > Book: http://tinyurl.com/3xqb7 > > > MVP -- Microsoft Firewalls (ISA) > > > > > > > > > > > > > -----Original Message----- > > > > From: isapros-bounce@xxxxxxxxxxxxx > > > > [mailto:isapros-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Harrison > > > > Sent: Wednesday, August 29, 2007 1:10 PM > > > > To: isapros@xxxxxxxxxxxxx > > > > Subject: [isapros] ISA and SAN Certs > > > > > > > > > > > > Another isablog for your reading pleasure. > > > > > > > > > > > > http://blogs.technet.com/isablog/archive/2007/08/29/certificat > > > > es-with-mu > > > > ltiple-san-entries-may-break-isa-server-web-publishing.aspx > > > > > > > > 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. > > > > 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.