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#1 2021-05-17 10:01:25

Blyzard
Member
Registered: 2021-05-17
Posts: 3

Office365 SMTP Support

Hi,

I don't know exactly if this should be posted around this forum section "Feature requests & Improvements" or somewhere else.
But at least, i have some interesting bits about the Office 365 support.

I was having some issues sending emails from XSIBackup-DC to an Office 365 SMTP server.
The errors message were:

501 5.5.4 Invalid domain name [PAYP264CA0002.FRAP264.PROD.OUTLOOK.COM]
501 5.5.4 Invalid domain name [PAYP264CA0002.FRAP264.PROD.OUTLOOK.COM]
503 5.5.2 Send hello first [PAYP264CA0002.FRAP264.PROD.OUTLOOK.COM]

In case you would be interested as an upgrade or simply a note in your documentation, here are the changes i have made to make it work:

- Office 365 can be extremely picky on EHLO. You have some insights on Microsoft 365 EHLO issues here.

- So i opened the XSIBackup-DC installation path, and in ./etc/sendmail, i first made a backup of the file, then on line 424, changed the command:

echo -ne "ehlo ${HOSTNAME}${nl}"

to

echo -ne "ehlo${nl}"

- Also to mention that i used TLS as protocol. My configuration look like this in ./etc/smtpsrvs.conf:

1;smtp.office365.com:587;backup@mydomain.domain;backup@mydomain.domain;MyPassword;yes;TLS;0

Of course the email domain and password are anonymized in this example !

Then everything worked fine.
By using ./xsibackup --smtp-test , i now receive the test email !

Regards.

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#2 2021-05-18 06:03:49

admin
Administrator
Registered: 2017-04-21
Posts: 2,055

Re: Office365 SMTP Support

Thank you very much for your feedback.
The domain should follow the EHLO keyword:
RFC 5321 EHLO

If what you descibe is correct, you are using a service that does not follow protocol standards. We may be able to add some helper, in any case we recommend that you switch to a service which is compatible with the SMTP protocol.

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#3 2021-05-18 08:49:52

Blyzard
Member
Registered: 2021-05-17
Posts: 3

Re: Office365 SMTP Support

Indeed, it seem that for some reasons, Microsoft Office 365 does not respect the RFC.
It is still the only solution i have found to send emails to Office 365 SMTP servers.

This is the email provider of my business client, i don't have the choice to change.
Thanks for your additional informations.

Have a nice day

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#4 2021-05-18 09:25:28

admin
Administrator
Registered: 2017-04-21
Posts: 2,055

Re: Office365 SMTP Support

Thank you for your feedback, I'm sure many users will find it extremely useful. As said, we'll try to add a helper to ease Office365 compatibility in some future version.

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#5 2021-05-26 17:29:43

admin
Administrator
Registered: 2017-04-21
Posts: 2,055

Re: Office365 SMTP Support

We added a helper in the way you suggested. Still, using services that ignore standards is not something we recommend. They arbitrarily obliterate the server in the EHLO command, why not something different tomorrow?, what kind of confidence as a user can you expect from that kind of attitude?.

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#6 2021-05-26 18:08:34

Blyzard
Member
Registered: 2021-05-17
Posts: 3

Re: Office365 SMTP Support

I agree with you, and it's a shame that Microsoft didn't managed to respect this RFC.

I also don't recommand that things must be changed in some fancy way in order to work, as you stated the RFC was made in order to make this works everywhere if it's respected.

My final thought of this is RFC compliance VS the service provider size and usage, assuming that fixing the "faulty" part is not something cumbersome...

If it was my own full environment, i may have used other email service provider, providing a different subdomain and MX entries in DNS in order to use an other "managed" mail service that is RFC compliant instead.

Thank you for your work and your infos.

Where is the helper located for the change ?
Is this available in the last XSIBackup-DC build ?

Thank you !

Have a nice day.

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#7 2021-05-27 08:45:52

admin
Administrator
Registered: 2017-04-21
Posts: 2,055

Re: Office365 SMTP Support

It's applied by automatically detecting the office365 string, we might make it optional in the future.

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