| title | SMTP Authentication |
|---|---|
| description | |
| category | Features |
For sending outgoing emails through the Postal SMTP server you will need to generate a credential through the Postal web interface. This credential is associated with a server and allows you to send mail from any domain associated with that domain (or the organization that owns the domain.)
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). 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.
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.
If you have enabled "Allow Sender Header" for the server, you can include this domain in the Sender header instead and any value you wish in the From header.
Postal has the option to authenticate clients based on their IP address. To use this, you need to create an SMTP-IP credential for the IP or network you wish to allow to send mail. Use this carefully to avoid creating an open relay.