exchange 2013 - connection from app to imap

Question

exchange 2013 - connection from app to imap

Jack 66

Hello,

We have an app that is using exchange 2013 and connects to it via IMAP. Recently in app logs we noticed errors "Error connecting with SSL. error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number)".
The Application is configured to connect with exchange using domain user/Pw port993 and tls 1.1version.
I search in IMAP logs on exchange but I did not found anything, also I did a test imap connectivity but it also succeeded.

Apart of this application everything is working fine. Do you have a clue where I could check what is wrong?

Kael Yao 37,746 Reputation points Moderator

2020-12-18T08:54:07.703+00:00

Hi,
I am writing here to confirm with you how thing going now.
Do you have any updates on this question?

If the response is helpful, please click "Accept Answer" and upvote it.
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Ashok M 6,846 Reputation points

2020-12-30T06:04:12.287+00:00

Hi @Jack

Its been a few days since we got an update on this. If the above suggestion helps, please click on "Accept Answer" and upvote it. This will be beneficial to other community members as well. Thanks for understanding.

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Kael Yao 37,746 Reputation points Moderator

2020-12-18T08:54:07.703+00:00

Hi,
I am writing here to confirm with you how thing going now.
Do you have any updates on this question?

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.
Ashok M 6,846 Reputation points

2020-12-30T06:04:12.287+00:00

Hi @Jack

Its been a few days since we got an update on this. If the above suggestion helps, please click on "Accept Answer" and upvote it. This will be beneficial to other community members as well. Thanks for understanding.

Answer 1

Ashok M 6,846

Hi,

Based on my knowledge, looks like issue is with TLS 1.1. Can you please change it to TLS 1.2 in your application and check?

https://techcommunity.microsoft.com/t5/exchange-team-blog/exchange-server-tls-guidance-part-3-turning-off-tls-1-0-1-1/ba-p/607898

Did you test the IMAP connectivity with SSL/TLS connection type parameter?

https://learn.microsoft.com/en-us/powershell/module/exchange/test-imapconnectivity?view=exchange-ps#parameters

Check if the certificate has been assigned with IMAP service. If using wildcard, then update the X509CertificateName in IMAP settings

Set-IMAPsettings –X509CertificateName ""

https://www.azure365pro.com/how-to-enable-and-configure-pop-imap-in-exchange-2013/
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

If the above suggestion helps, please click on "Accept Answer" and upvote it

Ashok M 6,846 Reputation points

2020-12-15T06:28:50.933+00:00

Hi,

Just to check if there are any updates. If the above suggestion helps, please click on "Accept Answer" and upvote it. Thanks for understanding.
Jack 66 Reputation points

2020-12-16T16:13:48.457+00:00

Hi,

Unfortunately when we changed TLS 1.1 to TLS 1.2 still this not helped.
I also based on your suggestion tested IMAP connectivity by executing test-Imapconnectivity on a particular user mailbox and this test was passed.

However I'm struggling how to properly assign wildcard certificate for IMAP, as in the certificate subject we have "*.domain.com" name. How should I properly construct this query "set-Imapsettings -x509certificatename" not having exact name ? Can it be fqdn of our exchange server ?
Ashok M 6,846 Reputation points

2020-12-16T16:29:52.18+00:00

It will be the FQDN for IMAP. For instance, if IMAP connection is mail.domain.com then it will be set-Imapsettings -x509certificatename mail.domain.com

https://learn.microsoft.com/en-us/powershell/module/exchange/set-imapsettings?view=exchange-ps#examples (Example 5)
Jack 66 Reputation points

2020-12-16T19:21:09.153+00:00

Ok, after these suggestions i was able to set Outlook client via IMAP, without any problems, so I assume IMAP is was properly configured.

Still however I cannot connect via an external app, and in logs I see the same error "IMAP4 mailbox exception for test@keyman .com (Error connecting with SSL. error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number).

i checked App basic email configuration and all the settings like, imap password and domain user name, exchange IP server, tls (1.2), imap port 993 are set. Are you able to suggest if there is something else where I should look ?

Thank you in advance.
Ashok M 6,846 Reputation points

2020-12-17T05:18:34.16+00:00

Glad to know that IMAP is working when configured through outlook.

How are you connecting from app to Exchange server? When you say external, is it connecting from public ip? Is it using any load balancer IP or FQDN or IP? Can you try with the FQDN used in X509CertificateName in the application?
Also, can you check if the app is able to connect without using SSL|TLS I.e on port 143.

Also try setting ExternalConnectionSettings in Set-IMAPsettings

https://learn.microsoft.com/en-us/exchange/clients/pop3-and-imap4/configure-imap4?view=exchserver-2019
Ashok M 6,846 Reputation points

2020-12-22T06:37:58.34+00:00

Hi,

Do above suggestions help? Please click on "Accept Answer" and upvote it. Thanks for understanding.
Jack 66 Reputation points

2021-01-20T10:10:39.153+00:00

Sorry but it took some time till I get access to faulty Application and check it.
In turned out that it started working when I set on App TLS 1.0.
I checked and it looks that in order to start work with newer TLS's I need to install Cumilative updates :), so now I need to prepare to install CU23.
Ashok M 6,846 Reputation points

2021-01-20T10:53:39.157+00:00

Glad to know the suggestion helped. Cumulative update is not only for TLS but also to stay in supported environment.

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exchange 2013 - connection from app to imap

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