About SMTP Auth

notteumani

Hi.
I’m using mailcow with nextcloud. I can connect my email account in nextcloud as a sender. Here I notice after setting up the server address, port and an existing email address, I can leave the SMTP username and password blank sending emails.
But I am assuming that I am supposed to be authenticated? If it’s not necessary, does it mean that anyone knows my mail server address, port and an email address under my domain is able to send emails using SMTP?
I don’t want my server to become a spam server. Thanks very much if someone can answer this.

heavygale

Only senders in the trusted local network can send mails without auth.
You can disable thie behaviour if you want:
https://mailcow.github.io/mailcow-dockerized-docs/firststeps-rfc-1918/

notteumani

heavygale Thank you very much! During the installation of mailcow I am not asked of anything about SMTP username and password. Where can I find and change them? Thanks a lot.

heavygale

There is no username or password needed to send mails, if the sender is in the trusted local network.
Therefore netcloud, if run on the same host in the mailcow docker network, can send mails without auth.
(At least that’s what it looks like to me ^^)

notteumani

heavygale Thanks! If I have other services not in my local network and I want to use SMTP sending. Will the username and password be the email account and passwd?

heavygale

The same settings as you use in other mail clients, username is the full email address.

notteumani

heavygale Thank you very much!

rassemdev

notteumani Can you share your smtp setting? what you used on those fields?
MAIL_DRIVER=
MAIL_HOST=
MAIL_PORT=587
MAIL_USERNAME=
MAIL_PASSWORD=
MAIL_ENCRYPTION=

pkernstock

rassemdev The last post was one year ago, please open a separate discussion. Closing this one.