Skip to content

Added more details on SMTP authentication #70

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: main
Choose a base branch
from
Open

Added more details on SMTP authentication #70

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 24 additions & 1 deletion content/3.features/smtp-authentication.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,9 +11,32 @@ For sending outgoing emails through the Postal SMTP server you will need to gene
When authenticating to the SMTP server, there are three supported authentication types.

* `PLAIN` - the credentials are passed in plain text to the server. When using this, you can provide any string as the username (e.g. `x`) and the password should contain your credential string.
* `LOGIN` - the credentials are passed Base64-encoded to the server. As above, you can use anything as the username and the password should contain the credential string (Base64-encoded).
* `LOGIN` - the credentials are passed Base64-encoded to the server. As above, you can use anything as the username and the password should contain the credential string (Base64-encoded). Check the example below:
```
# Example snippet:
# Let's assume, you use "$ telnet <smtp_server_ip_address> 25"
Trying <smtp_server_ip_address>
Connected to <smtp_server_ip_address>
Escape character is '^]'.
220 postal.example.com ESMTP Postal/GWLMYC7F

# You start from here:
HELO example.com
250 postal.example.com
AUTH LOGIN
334 VXNlcm5hbWU6
c29tLXNtdHAtdXNlcg== >> you would need to enter any or your smtp username in base64 - try command - "echo -n 'your-username' | base64"
334 UGFzc3dvcmQ6
OElLM0Q4ckFOQW9obTl0QnpQcVpkRlhi >> you would need to enter your smtp key generated in the web UI in base64 - try command - "echo -n '8IK3D8rXXNAohm9tBzPqZdFXb' | base64"
235 Granted for <organization-name>/<mail-server>
```
* `CRAM-MD5` - this is a challenge-response mechanism based on the HMAC-MD5 algorithm. Unlike the above two mechanism, the username does matter and should contain the organization and server permalinks separated by a `/` or `_` character. The password used should be the value from your credential.

To get the `Credentials`, you can go to the Postal home > Credentials > Click or Add a Credential > Copy the username and the generated key.

![smtp_credentials](https://github.com/user-attachments/assets/be0bf380-b369-49d8-83b5-e824561e0c15)


## From/Sender validation

When sending outgoing email through the SMTP server, it is important that the `From` header contains a domain that is owned by the server or its organization. If this it not valid, you will receive a `530 From/Sender name is not valid` error.
Expand Down