I have an e-mail account, let's say me@server.com, which allows me to write and receive e-mails. I have also an alias, let's say me@alias.com, that redirects the e-mails written to this address to me@server.com. What I want is to send e-mails from Thunderbird using the server of me@server.com but with sender address me@alias.com.
I tried to use the identity feature of Thunderbird. The problem is that it seems that Thunderbird uses the e-mail of the identity to fill in the "MAIL FROM" field of the smtp protocol, and that does not please the server.com server. I get an error "553 5.7.1 invalid sender". I would like to customize the "From" field of the mail content (with me@alias.com), but leave untouched the "MAIL FROM" one (i.e. uses me@server.com for this field).
To be clear, I do not really care about fully masking the address me@server.com. It would not be a problem if that address appeared in the metadata of the e-mail. I just want that at first glance the e-mail seems to have been sent from me@alias.com.
