How to setup ‘send-From’ address in Gmail
Go to Gmail Settings » Accounts and Import » Send mail as: » Add another email address that you own »
Name: Your Name
Email address: firstname.lastname@example.org
Treat as an alias.
Next Step »
SMTP Server: mail3.gridhost.co.uk
Username : email@example.com
Secured connection using TLS (recommended)
Add Account »
Finally, you MUST confirm verification to complete this procedure – click link in email Gmail will send you and then click CONFIRM on webpage.
Now when you want to send-from any of your addresses in Gmail: click on Compose and adjust the From field! See “How to ‘send-From’ address in Gmail” FAQ.