# Filter known-bad sender domains from your mail-receiver
**URL:** https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760
**Category:** Sysadmins
**Tags:** how-to
**Created:** [May 27, 2019, 4:52am UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760 "2019-05-27T04:52:40Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@mpalmer](https://meta.discourse.org/u/mpalmer)
#### Post date: [May 27, 2019, 4:52am UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/1 "2019-05-27T04:52:40Z")
If you [run your own incoming mail](https://meta.discourse.org/t/straightforward-direct-delivery-incoming-mail/49487), and you find that you’re getting more abusive mail than you’re willing to tolerate, this guide is for you! It’ll show you how to configure your `mail-receiver` container to block e-mail from any domain on a list you create, and how you can add and remove domains from that list over time.
# Setup
1. Using the [custom Postfix configuration guide](https://meta.discourse.org/t/customising-direct-delivery-postfix-configuration/118759), configure your `mail-receiver` container to have an `/etc/postfix/shared` volume (see the “Addendum” section at the bottom).
2. Create an empty file **on the host** , in `/var/discourse/shared/mail-receiver/etc`, named `sender_access`, by running the following command as `root`:
3. Using the [custom Postfix configuration guide](https://meta.discourse.org/t/customising-direct-delivery-postfix-configuration/118759), set the following environment variable:
Your Postfix system is now ready to accept domains to block.
# Blocking and unblocking domains
The list of domains you want to block is maintained in the file `/var/discourse/shared/mail-receiver/etc/sender_access` on the host. The format is straightforward: just a list of domains, one per line, with the word `REJECT` after it. Here is an example:
```plaintext
example.com REJECT
example.org REJECT
# etc
```
There are other possibilities you can use instead of `REJECT`, but we won’t cover them in this guide; see [the fine manual](http://www.postfix.org/access.5.html) if you want to get super-fancy.
Thus, to add or remove a domain from the list of blocked domains, simply add or remove the relevant line from the file, by editing it **as `root`**.
There is one final step that needs to be taken after editing this file: reloading Postfix. It doesn’t automatically notice that a change has happened, and needs to be told. The quickest and least disruptive way to do this is to send a special signal to Postfix, using this command:
```plaintext
docker kill -s HUP mail-receiver
```
If you then examine the logs for the `mail-receiver` container, you should see Postfix mentioning a config reload.
That’s it. Enjoy a less-abused mail system.
---
### Author:  [@tobiaseigen](https://meta.discourse.org/u/tobiaseigen)
#### Post date: [May 27, 2019, 5:24pm UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/2 "2019-05-27T17:24:28Z")
Thanks, Matt! Much appreciated. I owe you at least a 🍺 for this super helpful howto. I have now implemented the above and added the offending domains to it - I’ve let it go for an hour and so far it’s been quiet.
One clarification: In setup above, you use the `/var/docker..` path when I think you mean `/var/discourse..` - though I suspect different instances may use different paths depending on when they were set up. These days I suspect most people use `/var/discourse..` which is also reflected in the other howto you link to for setting up direct delivery.
---
### Author:  [@mpalmer](https://meta.discourse.org/u/mpalmer)
#### Post date: [May 28, 2019, 4:45am UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/3 "2019-05-28T04:45:09Z")
> [@tobiaseigen](#):
>
> In setup above, you use the `/var/docker..` path when I think you mean `/var/discourse..`
You are correct. For hysterical raisins we use `/var/docker` internally, so that’s the path that comes to mind. I’ve updated the howto.
---
### Author:  [@tobiaseigen](https://meta.discourse.org/u/tobiaseigen)
#### Post date: [May 28, 2019, 2:02pm UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/4 "2019-05-28T14:02:58Z")
> [@mpalmer](#):
>
> hysterical raisins
hysterical. 😆
---
### Author:  [@satonotdead](https://meta.discourse.org/u/satonotdead)
#### Post date: [April 9, 2020, 9:03pm UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/5 "2020-04-09T21:03:06Z")
Can we implement a more robust system to block incoming spam or maybe using more possibilities (detailed in Postfix manual) could be enought?
Thanks for that guide!
---
### Author:  [@mpalmer](https://meta.discourse.org/u/mpalmer)
#### Post date: [April 12, 2020, 9:39pm UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/6 "2020-04-12T21:39:46Z")
Yes, you can certainly implement a more robust system to block incoming spam.
---
### Author:  [@satonotdead](https://meta.discourse.org/u/satonotdead)
#### Post date: [April 12, 2020, 11:05pm UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/7 "2020-04-12T23:05:32Z")
Can you share some link or idea to start with?
---
### Author:  [@codinghorror](https://meta.discourse.org/u/codinghorror)
#### Post date: [April 13, 2020, 3:09am UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/8 "2020-04-13T03:09:37Z")
Whole literal books could be written about spam and email servers. Is it really fair to ask us for that level of instruction? Perhaps give it a google or two?
---
### Author:  [@satonotdead](https://meta.discourse.org/u/satonotdead)
#### Post date: [April 13, 2020, 3:39am UTC](https://meta.discourse.org/t/filter-known-bad-sender-domains-from-your-mail-receiver/118760/9 "2020-04-13T03:39:46Z")
Sorry, it’s not the idea. I just ask for personal recommendations from Discourse experienced users.
I’ll look into it by my own, of course.