Configure postfix to handle multiple domain email addresses

I have a Linux Ubuntu system, Postfix has been setup to run multiple domains. The problem is when I send email from it shows up as being sent from . I'm sure this is a small problem and so I expect it to be completed in no more than an hour. Everything has been set up and configured, below is the example I have used for postfix 1 /etc/postfix/[login to view URL]: 2 virtual_mailbox_domains = [login to view URL] ...more domains... 3 virtual_mailbox_base = /var/mail/vhosts 4 virtual_mailbox_maps = hash:/etc/postfix/vmailbox 5 virtual_minimum_uid = 100 6 virtual_uid_maps = static:5000 7 virtual_gid_maps = static:5000 8 virtual_alias_maps = hash:/etc/postfix/virtual 9 10 /etc/postfix/vmailbox: 11 [login to view URL] 12 [login to view URL] 13 # Comment out the entry below to implement a catch-all. 14 # @[login to view URL] [login to view URL] 15 ...virtual mailboxes for more domains... 16 17 /etc/postfix/virtual: 18 postmaster You will need to work on this problem through TeamViewer 9, so please do not ask me for direct server access. You must also keep in contact with me through a messaging service. Please do not bid if you cannot commit to my terms or complete the job.