I have a server running python, php, perl, ruby, and I have couple applications which also send mail. I was wondering in case if one of the applications don't specify a from email address, the sender email address is set to http@example.com and the sender name was "http".
I was able change the sender name by going into /etc/passwd and changing the name to what I wanted, but how do I change http@example.com to admin@example.com?
knittl
You can use the smtp_generic_maps of postfix to rewrite email headers for outgoing smtp mail:
user:~$ echo "http@example.com admin@example.com" >> /etc/postfix/generic
user:~$ echo "smtp_generic_maps = hash:/etc/postfix/generic" >> /etc/postfix/main.cf
user:~$ postmap /etc/postfix/generic
user:~$ service postfix restart
来源：https://stackoverflow.com/questions/9538817/how-to-change-default-email-address-for-postfix