OVERVIEW: Information on Blocked Emails
Article ID: 427 | Last Updated: Fri, Sep 9, 2016 at 10:28 AM
Information on Blocked emails
Clemson has been repetitively attacked by several spammers in the recent past which degrades our email reputation. To prevent this, we have implemented a spam filtering service to help control any unwanted emails. While we are aware that our filters will sometimes block legitimate emails, it is critical to protect ourselves and have our defenses up.
We apologize for any frustration this may cause you and the intended recipient.
Please click on the relevant link below if your message keeps getting blocked.
Access Denied Errors
If you are attempting to send email to Clemson University (@clemson.edu) from an outside agency or company (e.g. @dnr.sc.gov) and are receiving error messages such as
"Access denied. IP name possible forged"
"Access denied. IP name lookup failed"
Clemson may be rejecting your email because our email routing now requires sending domains allow us to successfully complete a Reverse Domain Name Server Lookup. This lookup verifies that the domain name is valid by comparing the IP address from which the message was sent with the IP address registered for the domain name. This configuration has become standard protocol in email processing.
To solve this issue, your agency or company must change their mail routing configuration as well. Information about this configuration can be found at http://tools.ietf.org/html/rfc1912 (refer to section 2.1) and http://en.wikipedia.org/wiki/FCrDNS.
Sending error reports
If you are a technical support person at an agency or company attempting to send email to Clemson and would like assistance, we first recommend sending an email to 'firstname.lastname@example.org' for assistance. If those messages are being blocked, we have set up an alternative Clemson postman address at email@example.com for you to forward error messages to. Please be aware that the postman account is not the primary means of communication from our email admins and you may not receive an immediate response.
Whitelisting your domain
To protect our email reputation, Clemson does not whitelist any domain other than those that meet very stringent guidlines. If your company keeps getting blocked by our spam filters, please send an email to firstname.lastname@example.org with the recipient and sender name, as well as the subject of the email. We will then view the email, and once verified, release your message to the end user. If requested we will also adjust our filters, on a case by case basis, to try and help prevent the block from happening in the future. Please keep in mind that this does not mean that all of your messages will be delivered as our ProofPoint filters 'learn' what is and is not spam over time.