Check users mail address

HCL Domino Domino Forum
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1

Dear collegues,

I have a Domino 14 server and will use this server as SMTP mail relay server with authentification.

This work very well, but it is also possible for the sender of mail to set a different sender address like in user document mail address.

How can I force that the address must be the same to aczept the mail?

Thank you for your answer.

2

Pse go to configuration in domino directory , Router/SMTP- Restrictions and Controls-SMTP Outbound controls

Configure .. allow messages to be sent only from...

Or deny msgs to be sent by

Or add more complex rules under rules tab

You should be able to figure out something, im sure.

Hope this helps

3

Thank you for your answer, but this will not prevent that user1 sending his mails with the mail address of user2.

Allow messages to be sent or rules, are also not a solution because I a have more as 100 users.

I want only that the user what login should send with the own mail address.

4

What you are looking for is an override for INetFrom field with the user that logged in for authenticated SMTP. If John Doe connects to your Domino SMTP, he shall only send on behalf of John Doe, right?

On Notes clients SMTPTranslateSpecial=1 does the job, but I don't know if it works fpr SMTP relays, too.

The parameter overwrites the the INetFrom with the address from the senders person document.

https://support.hcl-software.com/csm?id=kb_article&sysparm_article=KB0037196

On a Notes Client it prevents the user from setting an alternative "fake" sender address in the location document.

Maybe HCL can tell us if it works on SMTP relays, too, or if there is an equivalent setting available.

Regards

Friedhelm

5

Hello,

Please add following parameter on server notes.ini using "set config" command to meet your requirement.

SMTPVerifyAuthenticatedSender=1
Note: SMTP task restart is required after applying parameter.
Description: Specifies whether the SMTP server requires mail sent during an authenticated
session to be from the internet address of the authenticated user.
0 - Do not require the sender to use their internet address
1 - Require the Sender, or From, if Sender header does not exist, to match the internet address
of the authenticated server.
Basically, it verifies whether the email address of the sender in the Person document matches. For
example, suppose the sender is John Doe, whose email address is John.Doe@example.com, but the
“From” email address is incorrect, say bogus.user@example.com
Please refer the following published white paper for reference:
https://support.hcl-software.com/csm?id=kb_article&sysparm_article=KB0103502

Regards,
Chaitanya Y
6

Thank you Yalavarthy Chaitanya, this is what I want.

Have a nice day.

7

I understand that even though you have enabled SMTP authentication on the Domino server to relay emails outside your Domino domain, you wanted to avoid email spoofing from the authenticated sender.

You can refer the document on "Understanding SMTP authentication, securing your Domino server from spam, and using DKIM and SPF to secure Domino"

Read the page on 19 to 20 how this can be avoided using the ini "SMTPVerifyAuthenticatedSender"

When this parameter is enabled on the Domino server. Server will make sure it validates the From Address against the authentication email address. logs reports as below when it doesn't match.

[0820:0008-10E8] 11/21/2024 01:21:25 AM SMTP Server: Message rejected. Authenticated user John Doe/example
from host 192.168.0.105 sending mail from bogus.user@example.com failed to match directory address
John.Doe@example.com

Thank you

Regards

Shrikant J