I use postfix (basically postfix admin) to define my e-mail inboxes and SMPTs. Say I have a one e-mail inbox:


Now I have a few aliases. Say I have the alias:


Now the last alias receives e-mails and puts them in the first inbox. I can login to that inbox and receive e-mails from that alias.

The problem:

Now I would to send e-mails from that alias. I want the sender to be maria@mydomain.com. How can I do that? I can't login to my smtp server with that alias.

Please advise.

  • In case you -1 the question, please explain why you're doing this. Be more constructive than judgmental. Jan 26, 2016 at 10:53

2 Answers 2


You can't login using an alias, because it's not an email account, just a pointer to a real account. If you want to login using it, you need to create an account with the same name (and had to delete the alias first).

But all if you need is to send an email with that address as from address, you may setup the email client software accordingly. It is possible to configure more than one optional email addresses, and one of them can be selected as sending address while sending email.

For example: here is How to send from other email address in Outlook 2013. But there are some issues that needs to be noted (quoted from above link, applicable in general):

Issues sending from other email address

Please note that:

  • such emails sent from other email addresses have a higher probability to be marked as spam emails (because they are not sent through an authenticated connection of the “From” email address);

  • if the person receiving the email replies to it, the reply is going to be sent to the other email addresses that was specified in Outlook. So make sure you actually have access to this email address, otherwise you will not get to see the email replies;

  • the person receiving the email can see that the email was sent through a different email account. As you can see below (the photo is in the link above), Gmail shows that the email was sent through a different domain: Email sent from other address.

As a final comment, don’t think about using the “Send from other email address” feature as a tool to send spam! Obviously, you shouldn’t think to send spam emails anyway, but this Outlook 2013 feature actually uses the SMTP email server of your Outlook account, meaning that – if your email is marked as spam – it can be tracked back to your actual email account / SMTP server.

For Thunderbird you can do this by configuring multiple identities. Here is how: Using Identities in Thunderbird

  • Thanks. Is there a way to do this with Thunderbird? Jan 26, 2016 at 10:29
  • Yes, see my updated answer.
    – Diamond
    Jan 26, 2016 at 10:38

You have two options, depending on your postfix restrictions and the type of application/client you are using to send the email.

  1. You can rename your account as your alias name, and use the alias' email address.

  2. Use your the alias address directly within the MAIL FROM request.

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