Using Variable Envelope Return Paths
With the Capture Email Replies feature, email sent from lists, records, and transactions automatically saved to the contact record. It also saves to the record of the associated entity before being sent to your login email address. This is accomplished through the use of variable envelope return paths, or VERPs.
VERPs route email messages to NetSuite servers so that they can be recorded in NetSuite and then forwarded to the recipient. The sender and recipient addresses are not changed or hidden by VERPs. The use of VERPs is considered a best practice measure and complies with the mass email policies of large ISPs and email providers. No setup is required for VERPs.