Update 4/3/2015 12n: Our reputation has improved with many providers. Things appear to be returning to normal and messages should go through.
Update 4/1/2015 9a: We are still experiencing issues with many providers. We continue to monitor the situation.
UPDATE from VT Mail Team with more technical details (provided 4/1/2015 2:50p):
A technical explanation, from the mail team, about the current email issues:
During the weekend of March 21st, compromised machines belonging to Virginia Tech affiliates caused an inordinate amount of spam to pass through Virginia Tech email servers. As a result, many sites blacklisted us via a variety of RBL's (http://www.webopedia.com/TERM/R/RBL.html) and resulted in a poor reputation on SenderBase (https://www.senderbase.org/). This resulted in bounce back emails when sending email to many organizations and companies.
By the end of last week, we had managed to clean up the 500,000 message in the queue, head off much of the spam, and by the end of the week things were improving for the delivery of emails.
Over last weekend, the problem with compromised machines sending spam reoccurred. This resulted in another poor reputation for @vt.edu emails on SenderBase. Again, we managed to clean up the 500,000 messages in the queue, head off much of the spam, and by last night (3/31/15), things were starting to look better and our reputation was improving.
As part of our initiatives to "Think like a spammer," we started changing the IP addresses of the Outbound Mail Relays. New IP = New Reputation = No Blacklists. We had to do this eventually anyway, because we need to move from the old to the new load balancer. And it's a trick we're probably going to use again. However, it appears that last night, at least from some initial results that some hosts hung on to our DNS records longer than the timeouts indicate they should have. Hopefully these folks will soon detect the new DNS records.
Update 3/31/2015, 5pm: Our email reputation has improved with some of the major mail systems. We are still having issues with a few providers and will continue to monitor the situation.
Update 3/31/2015: We are still experiencing issues with outgoing mail due to blacklist/poor reputation. Our mail team is working diligently to resolve the issue completely. We appreciate your patience and apologize for any inconvenience.
Due to email/virus infection over the weekend, outgoing email from vt.edu is being blacklisted and/or blocked due to poor reputation. You may receive bounceback email stating "554 Your access to this mail system has been rejected due to the sending MTA's poor reputation," or something similar. Our mail team is actively working to get unlisted on the blacklists and off the reputation filters. Reputation recovery can take anywhere from a few hours to just over one week to improve, unfortunately speeding up the process is not really possible. In the meantime, if there are recipients whom you cannot contact, we would recommend that you arrange to contact the recipient via alternative means. We apologize for any inconvenience.
**As a reminder, if you receive any email containing a .zip or .exe file, and you do not know who it is from or were not expecting it, DO NOT open the file.**