Its not clear if you need to enable email relaying, but just in case, I've included two parts of the following Success Community Post, the latter of which likely applies most (in reverse) to what you need to do. Note that in another post, it appears that in the Winter 13 release
no-reply@ may have been changed to
Email relaying is using an email server to send email that did not
originate on the email server. Email relaying is a Feature Activation
and can only be enabled on Professional, Enterprise, Unlimited, and
Developer Editions of Salesforce. Companies set up email relaying to:
Route all email through their own email servers to avoid the
appearance of email spoofing by Salesforce.com. Email spoofing is the
forging of email headers to make messages appear as if they came from
someone other than the original sender. Store copies of all email as
required by government regulations in various industries. Apply
existing content filters that scan messages for data and content that
is not approved to be sent out through company email. Run outbound
email through antivirus software before sending it to customers.
Append data such as company-wide disclaimers at the bottom of email
messages. You can set up email relaying for Salesforce-generated email
by configuring Salesforce to automatically route email through your
company's Simple Mail Transfer Protocol (SMTP) server. In order to
enable Email Relaying, we require that you review the following
1. Please provide any domain names that this may apply to and the IP address of the mail machine we will relay to.
When you are notified that the relaying feature has been activated, you should enable relaying for the following IP addresses:
184.108.40.206 to 220.127.116.11
18.104.22.168 to 22.214.171.124
126.96.36.199 to 188.8.131.52
184.108.40.206 to 220.127.116.11
18.104.22.168 to 22.214.171.124
126.96.36.199 to 188.8.131.52
Please provide contact information for the primary mail contact person- this is usually an IT person responsible for your mail server.
Will you use TLS? We recommend the use of TLS if possible to increase security in the server to server process. Once Email Relaying
has been enabled for your organization, a System Administrator must
enable this in Setup. This can be done by going to: Setup | Email
Administration | Email Relay Activation
The following was said in response to "do you know if it is possible when we
are doing relaying to set the "sent from" to a customer.com address instead
When an organization has selected the Enable Sender ID compliance
checkbox in Email Delivery options this complies with the Sender ID
framework. This automatically populates the Sender field in the
envelope of every email you send from Salesforce.
Mail servers using the Sender ID email authentication protocol verify
the sender of an email by examining the Sender and From headers of an
inbound email through a DNS lookup. If you do not select this checkbox
the Sender field is not included in the header and email delivery may
fail when a recipient email system performs a Sender ID check.
Note: all replies to these mails will still be delivered to the
correct "From" email address.
If you do not want the from address to contain this information you
will need to disable this functionality.
You can turn this feature off by clicking on:
Setup | Email Administration | Deliverability Locate the "Email
Security Compliance" section Uncheck the Enable Sender ID compliance
box Click Save