Always will always use the Return path address as the sender address when present.
First, Second, Third, Fourth allows you to prioritize this header for use as the SMTP sender address.
For example all those set to First will be checked first and the sender used if a valid address is found.
Then the second fields will be checked and used if present.
Last Resort will only use sender from this field if no others have been found.
First
Use From
Always will always use the From address as the sender address when present.
First, Second, Third, Fourth allows you to prioritize this header for use as the SMTP sender address.
For example all those set to First will be checked first and the sender used if a valid address is found.
Then the second fields will be checked and used if present.
Last Resort will only use sender from this field if no others have been found.
Second
Use Custom
Always will always use the custom field address as the sender address when present.
First, Second, Third, Fourth allows you to prioritize this header for use as the SMTP sender address.
For example all those set to First will be checked first and the sender used if a valid address is found.
Then the second fields will be checked and used if present.
Last Resort will only use sender from this field if no others have been found.
Never
Header
Use a custom MIME header address as the SMTP sender address
Default Sender Address
You can override the sender address used for missing senders using this setting.
Some email will have no suitable MIME addresses for the sender. The default behaviour is to use POP3_<account name/email> as the address.
Use this setting to specify your own sender address to use when no From MIME field is available.
NOTE: using an internal/local address may stop the email being processed for SPAM etc. The address should be a valid address external to your domain, which is not allowlisted.
Specify NONE to use a blank sender when sending the email on the next hop, if your server supports this.
This setting only controls the SMTP envelope sender address and will not affect replies to the email or the displayed From field in email clients
pop3@domain.com
Always use this sender
You can override the sender address used for ALL email using this setting. Note that the reply-to and displayed From field shown to recipients of the email
will not be affected. This setting only controls the SMTP envelope sender address