Microsoft 'blacklists' Oxford University in accidental 'spam' overload

Oxford University managed to accidentally overflow Windows Live services, triggering Microsoft's anti-spam technologies, resulting in the university being 'blacklisted'.

World leading college, the University of Oxford, has suffered an email outage, causing all outbound email sent to Windows Live accounts to bounce back.

The university's service update pages points the problem to Microsoft triggering a series of counter-spam measures, after a university department 'misconfigured' a mailing list last week. Over a million messages destined for Microsoft's services, including Windows Live and Hotmail, pushed Microsoft to enact automatic preventative measures to prevent its own systems from crumbling.

The side effects were felt, as describes the Oxford OUCS support pages:

"This meant that mail sent to any domains for which the Hotmail servers handle mail was being rejected. It also caused a worse side-effect (manifesting itself as a mail loop, in some cases rapidly filling the Nexus mailbox) for anyone who had set their Nexus [internal student email] account to forward their email to such addresses."

As a result, the university mitigated damage by trapping any email destined for a,,, and email addresses in their servers, creating a massive backlog of emails waiting to be sent.

The trap does not affect regional Windows Live domains, however, allowing students and staff to send email to other countries associated with Windows Live.

By this point, Microsoft had automatically 'blacklisted' Oxford's domain names, in measures normally enacted by spam-producing domains, only days after the initial email error. Oxford has been working with Microsoft to unblock the domain from email servers, to restore normal functioning email sending to Windows Live domains.

Oxford believes that the blacklist has now been removed, which should allow emails to be released from the university's servers -- but in batches as to not overflow the system again and trigger repeat anti-spam countermeasures. Leading nearly into a week since the disruption, email should now begin to be delivered.

Oxford University is to conduct a "full investigation" to determine how a department "caused such disruption" at a critical time of year, just as the new academic session was starting.