Anyone who uses Gmail with a “From” address that is different than their actual Gmail address is familiar with Gmail’s inserting an “On behalf of” in the sending information. For example, if your Gmail address is “JaneDoe@gmail.com”, but you have Gmail using your work address of “jdoe@example.com” as your “From” address instead, when you send email through Gmail, instead of your recipients seeing “From: jdoe@example.com”, your recipients may see “From: JaneDoe@gmail.com on behalf of jdoe@example.com.”