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Installed SSL certificate for OWA, but Outlook is trying to use it internally


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Posted

We run an Exchange 2010 SP1 server and mostly Outlook 2007 clients, with a few Outlook 2010. When I initially set it up, I used a self signed cert for everything, this of course meant a warning on OWA and also a warning the first time with Outlook 2010, which I assume would eventually be solved by installing an internal CA.

 

However I bought a wildcard SSL certificate to use with OWA and installed it. I set the binding in IIS for port 443 to use the new cert, works fine externally.

But now internal Outlook clients (even 2007) bring up a prompt saying the server name does not match the certificate - and when you view the certificate it is the one for mail.schoolname.org so no wonder it is complaining.

 

I still have the self signed cert on the server, so how do I set it so Outlook uses that rather than the external one? I have read a lot about internal URL paths this afternoon which can apparently produce this error, but when I have checked these settings in the EMC they all seem to reference the internal FQDN so I'm not sure that is the problem here?

Posted

Has you brought a wildcard cert for you domain it wouldnt match the internal name of the exchange server

 

for example

 

My internet address of our exchange is mail.theockendonacademy.com

 

Our server is called for example mail or exchange

 

Now they certificate you have will only match the outside world address, so anything for *.theockendonacademy.com

 

For the internal address i would find *.theockendonacademy.com eithier but the internal domain name is diffrent and that it doesnt you the domain address at the end

 

So you need *.theockendonacademy.com (outside) mail (inside)

 

This is why I wouldn't get a wildcard for exchange, I would have got a SAN certificate.

 

 

 

or it could be the case that you need to setup your outlook users to use you outside address instead of the internal address if possible

 

I think this is your problem, hope that helps

Posted

You could just put add an A record to your internal DNS that points mail.schoolname.org to the internal IP address of your exchange server...

 

I'd make sure that your exchange server was looking at an external DNS server for name resolution though...

Posted

Thanks, I was thinking that would be the problem. Bought the wildcard cert thinking it would cover this and our sharepoint server :( Only found out about SAN certs today...oh well, live and learn

 

I would imagine that setting the external address to resolve internally just to be able to use the same certificate is probably not a great idea?

Posted
You could just put add an A record to your internal DNS that points mail.schoolname.org to the internal IP address of your exchange server...

 

I'd make sure that your exchange server was looking at an external DNS server for name resolution though...

 

Makes sense, but yes it is a bodge, cautious as it adds a layer of complexity for no reason apart from saving money (and making the most of me buying the wrong cert)

Posted

You'll also need to set internal and external names for all these services, mostly in the excahnge sheel: Exchange 2007/2010 Web services and Autodiscover Ultimate Troubleshooting Guide

 

And in the EMC set the services attached to each cert by going to 'server configuration' and clicking the servername for the server you want to manage. then clicking the cert and attaching services

 

been having this fun with loadbalanced CAS roles recently ;-)

Posted
Would this be ok? QuickSSL® Premium For Only £68.00 - Secure Mobile Devices, Issued Within Minutes, Free GeoTrust® Site Seal (UK)

Or is there something cheaper? TrustICO were who I ordered the wildcard cert from, bit annoying as that costs about £130 compared to £30 for a single server cert but at least I only purchased for a year!

 

Just ensure you've enough SANs (you get 3 with that cert - so realname.fqdn + 3 others)

 

Ours is valid for:

 

mailserver.internaldomainname.school.region.sch.uk

 

With SANs for:

 

webmail.school.region.sch.uk

autodiscover.school.region.sch.uk

autodiscover.internaldomainname.school.region.sch.uk

mailserver.school.region.sch.uk

 

Autodiscover.* is for Outlook clients

  • Thanks 1
Posted
Just ensure you've enough SANs (you get 3 with that cert - so realname.fqdn + 3 others)

 

Ours is valid for:

 

mailserver.internaldomainname.school.region.sch.uk

 

With SANs for:

 

webmail.school.region.sch.uk

autodiscover.school.region.sch.uk

autodiscover.internaldomainname.school.region.sch.uk

mailserver.school.region.sch.uk

 

Autodiscover.* is for Outlook clients

 

Our external is mail.schoolname.org and that is the only one we use externally, would 3 not be enough in our case?

Posted
Also I'm assuming from the responses there is no way to continue using a self signed cert for internal Outlook clients and the wildcard cert just for OWA? I have both installed on my exchange server
Posted

1. Use an Internal CA or a 3rd party cert.

2. If using a 3rd party cert, configure your internal and external URL to the same namespace.

3. Easy thing would be to get SAN cert and include the FQDN of your exch server.

Posted
Yes but we're an independent school, would they still issue one?

 

Don't see why not, give it a go, just apply for one. They manually check the education certs so takes a little longer (a few hours), but if your education, why not.

 

Pete

Posted (edited)
Yes but we're an independent school, would they still issue one?

 

 

Yep any educational institution

 

for a san cert, you need to create the the cert request (so for you in exchange with at the end of the wizard you should have all you san names)

 

apply for the cert order order, has soon as soon as you get your cert order email with the order number make a support ticket and state you would like a free san cert and write down the following san name you need along with your order number.

Edited by pritchardavid
  • 1 year later...
Posted (edited)

help, I'm about to make a cert request but need some pointers on the last few fields. I've half filled it in but I think I need to make an ldap request to make sure I fill in the last few fields correctly.

 

New-ExchangeCertificate -GenerateRequest -DomainName bemail.beaminster.dorset.sch.uk, autodiscover.beaminster.dorset.sch.uk,  exchange.dcc-sch-4505.local, exchange -FriendlyName beaminsterschexchange -KeySize 1024 -PrivateKeyExportable:$True -SubjectName "c=US o=contoso inc, CN=server01.contoso.com" -Path c:\certrequest.txt

 

c should equal UK?

o ? I can't find organisation in Active directory?

cn should equal the servers local or public name?

 

 

external name bemail.beaminster.dorset.sch.uk

internal name exchange.dcc-sch-4505.local

 

I don't have the autodiscover service working (I think) but I don't see the harm in including it. All my 2003 and 2010 outlook clients work fine as do the owa clients. I have to set them up by hand but no biggie.

Edited by chazzy2501
Posted (edited)
Personally I would not do it this way. I would advise you if you haven't all ready is to add "beaminster.dorset.sch.uk" as a DNS zone in your internal DNS server(s). Add the bemail as a A Record in that zone. You can then configure your Exchange server to use the same name internally and externally (bemail.beaminster.dorset.sch.uk), this will make it a ton easier being the same. Personally to make sure you have not gone wrong with powershell code, you can create the SSL cert the the Exchange console. Edited by pritchardavid
Posted

@pritchardavid Yes, that is the way for single name certs. Which I now realize I have todo as the UC certs are not free :(

 

Do I have to setup a DNS Zone? I can already ping bemail.beaminster.dorset.sch.uk locally and get the local ip address. (and I can RDP to it using bemail)

 

This may upset my outlook clients as they connect to exchange.dcc-sch-4505.local ?

 

cheers

Posted
What is your internal domain? Is it... dcc-sch-4505.local? What did you request/got for your certificate in the end? Advantages of using the internal DNS zone is it quicker (doesn't have to access the I internet to find DNS records)

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