Copy All Mail
If you would like to have incoming messages routed to another e-mail address, enter the routing e-mail address into the E-mail field. There are additional options available including:
- Enabling or disabling the re-directing of messages by selecting the appropriate option.
- Keeping a copy of the re-directed messages in your account as well as forwarding to the requested e-mail address.
- Do not Redirect Automatic Messages: You can choose whether to have messages that are automatically generated re-directed to the requested email address or not.
Forwarding Action
The type of forwarding Action which is selected will noticeably impact how your email is forwarded to its destination. Three choices are available:
Send on behalf of this Account
The message is forwarded to the specified addresses. The From address in each forwarded email is changed to be the account you are forwarding from. This is typically not a desired feature, so this forwarding method is often not utilized.
SRS feature
Both of the following forwarding methods, support Sender Rewriting Scheme
The Sender Rewriting Scheme (SRS) is a scheme for bypassing the Sender Policy Framework's (SPF) methods of preventing forged sender addresses. to ensure forwarded email passes SPF Sender Policy Framework (SPF) is an email authentication method which ensures the sending mail server is authorized to originate mail from the email sender's domain. and DKIM DomainKeys Identified Mail (DKIM) is an email authentication method designed to detect forged sender addresses in email (email spoofing), a technique often used in phishing and email spam.
DKIM allows the receiver to check that an email that claimed to have come from a specific domain was indeed authorized by the owner of that domain. It achieves this by affixing a digital signature, linked to a domain name, to each outgoing email message. The recipient system can verify this by looking up the sender's public key published in the DNS. A valid signature also guarantees that some parts of the email (possibly including attachments) have not been modified since the signature was affixed. checks performed by the final recipient's mail service.
SRS Background
Click to Expand
The main objective of email authentication standards (SPF, DKIM, DMARC) is to prove an email is not spoofed and sent from the server that is authorized to send emails for a given domain. But what if a legitimate email server needs to forward emails to an account, hosted on a different server?
For example, a user john.doe@mycompany.com has a "Copy all Mail To" rule to forward to john.doe@external_domain.com.
If example@gmail.com sends and email to john.doe@mycompany.com and it is then forwarded to external_domain.com's mail server, that mail server will regard that email as having originated from mycompany.com when in fact it originated before that, from gmail.com. Because of this, the forwarded message will not pass the SPF check and the email will most likely be classified as "Spam" or rejected.
The Sender Rewriting Scheme The Sender Rewriting Scheme (SRS) is a scheme for bypassing the Sender Policy Framework's (SPF) methods of preventing forged sender addresses. (SRS), is a solution to forward emails without breaking any authentication standard by rewriting the envelope sender.
Example:
| Without SRS | With SRS |
|---|---|
|
The envelope of the forwarded email :
The external_domain.com email server will check gmail.com SPF DNS entry with mycompany.com server IP address, so the SPF verification will fail. |
The envelope of the forwarded email :
Where HHH is a hash and TT a timestamp. |
As SRS rewrites the email to use your own domain during the forwarding to the external server, the SPF checks will pass. The original DKIM signature will be tested with the header in the sender domain (example@gmail.com) and will pass as well.
Keep the Original sender Address
If this option is selected, a Redirect to action is used for this Rule. The message is redirected to one or several specified E-mail addresses. If several addresses are specified, they should be separated with a comma (,).
The "new sender" address is constructed as the E-mail address of the current Account.
The redirected message Return-path address is changed to be the account you are forwarding from.
- The redirected message Sender address is set to the "new sender" address.
- A Return-Path header field (if any) is changed to the X-Original-Return-Path field.
- Return-Receipt-To, Errors-To and DKIM-Signature fields are removed.
- Message-ID, Date, and Sender fields (if any) are renamed into X-Original-Message-ID, X-Original-Date, and X-Original-Sender.
- New Date and Message-ID fields are created.
Send unchanged Copy
If this option is selected, the Mirror to action is used for this Rule. The message is mirrored to the specified addresses (with minimal header changes). The redirected message Return-Path is preserved.
The message is mirrored to the specified addresses. Unlike the Redirect to operation, above, the Mirror to operation does not change the message headers, only the
Mirror to addresses
- A Resent-From header field is added. It contains the E-mail address of the current Account (without its Real Name).
- A Return-Path header field (if any) is changed to the X-Original-Return-Path field.
- Return-Receipt-To and the Errors-To fields are removed.
- X-Mirrored-by header field is added.