External Blacklists

It is possible for emails sent by an @unr.edu email account to get blocked by a third party email provider, and placed on a spam "blacklist". This can result in emails getting delayed, blocked, or bounced back to the sender with no clear indication as to why.. In the past, these delays and blocks have come from large, external email providers such as Yahoo and Hotmail.

While the reasons why this occurs are numerous, and should not all be listed (for security purposes - we don't want malicious people to get ideas), there are some common processes that result in the blacklist. The University works hard to ensure that these disruptions are minimal, and every effort is made to prevent them from occurring in the future.

Common Causes for the Blacklist

The most common reason for @unr.edu emails to get blacklisted is after a successful phishing attack. Many times, responding to a malicious email can result in that user's email account being used to send large amounts of spam emails. If an external email provider (such as Yahoo) detects a lot of spam coming from an @unr.edu email account, they may block the University from sending emails to their system until they are satisfied that the spam deluge has been controlled.

Malware or misconfigured computers may cause a system to spoof the University mail-sending servers. Either these systems will start sending a lot of unsolicited email, and get blacklisted, or the mere change in configuration will arouse suspicion from the third-party email providers and ultimately get blocked.

What Does OIT do About the Blacklisting?

For security reasons, it is inadvisable for us to list all the methods we entail to prevent the blacklisting from occurring. However, this lack of information should not be interpreted as a lack of action.

We run a number of tools internally that are designed to intercept and stop spam email from leaving and entering the University. Additionally, we act upon guidance from the large Email Service Providers that inform us of large phishing and spamming attempts, so that we can prevent those emails from reaching your inbox.

If a blacklist is detected, our Email Service systems administrators will contact the service blocking us to resolve the situation as soon as possible. In many of these situations, the block is automatically lifted after some amount of time. In other situations, we will work with their systems administrators to identify the cause of the block and ensure that it doesn't happen again.

Yahoo and Hotmail/MSN

We have found that emails sent to Yahoo and Hotmail/MSN addresses are the most likely to get blocked. We have worked hard to have these blocks lifted, but it can often take a surprisingly long time for email to start to get delivered again. If you receive a message that your email has been delayed, then you may want to look at these options:

  • All students and employees of the University are entitled to a University email address. Faculty and Staff can get an @unr.edu email address from our Exchange system, and students can get an @nevada.unr.edu email for life, powered by Google. These emails providers are highly unlikely to block legitimate emails.
  • You can try sending the email from an external address (such as a Gmail or Yahoo email account). These are free to set-up, unlikely to be part of the blacklist, but will lack the professionalism an @unr.edu or @nevada.unr.edu email account has.
For more information, please contact the OIT Support Center


Article ID: 117070
Fri 9/25/20 4:17 PM
Tue 1/19/21 11:59 AM