question

Sehwag-5088 avatar image
0 Votes"
Sehwag-5088 asked EricYin-MSFT commented

Unencrpyted connection between office 365 and edge server

Hi Admins,

I have emails that are being routed to onpremise edge server( smarthost) from office 365 through connector for a specific domain.

I see from the Security and compliance reports that TLS is not being used, emails between office 365 and Edge server are/is unencrypted.

I try to force tls from office 365 outbound connector and validate it with both options, Using third party CA cert as well as any digital self signed cert.

It returns an error matching this.

450 4.4.317 Cannot connect to remote server [Message=451 5.7.3 STARTTLS is required to send mail] [LastAttemptedServerName=edge.domain.com] [LastAttemptedIP=165.xxx.xx.xx:25]

I have checked on the receive connector it is auth mechanism is set to use TLS.

We are good to go from firewall side, what more could i check? what logs to check for find out why TLS auth is failing? basically what and where to look for?

Any help will be appreciated.

office-exchange-server-administrationoffice-exchange-server-mailflowoffice-exchange-server-connectivityoffice-exchange-hybrid-itpro
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

1 Answer

EricYin-MSFT avatar image
0 Votes"
EricYin-MSFT answered EricYin-MSFT commented

Hi,
Are you running a hybrid deployment or just routing some mails to the Edge server?
It's suggested to test with all firewalls dsiabled.
This error is usually seen when the cert for on-premise Exchange Default Frontend ReceiveConnector been changed, see these articles for more information:
https://www.petenetlive.com/KB/Article/0001631
https://docs.microsoft.com/zh-CN/exchange/troubleshoot/email-delivery/cannot-receive-mail-with-new-certificate
Or the cert is not updated between on-premise and online, then you need re-running the hybrid wizard and select the new cert.


If an Answer 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.


· 1
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

I am writing here to confirm with you how the thing going now?
If you need further help, please provide more detailed information, so that we can give more appropriate suggestions.


If an Answer 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.


0 Votes 0 ·