University of Cambridge Computer Laboratory - Delays to mail forwarded through cl.cam.ac.uk / cst.cam.ac.uk – Incident details

All systems operational

Delays to mail forwarded through cl.cam.ac.uk / cst.cam.ac.uk

Resolved
Major outage
Started 8 months agoLasted 21 hours 27 minutes

Affected

External Services

Degraded performance from 1:01 PM to 6:35 PM, Operational from 6:35 PM to 2:05 PM

Updates
  • Resolved
    UTC
    Resolved

    This problem has been fully mitigated.

  • Monitoring
    UTC
    Monitoring

    Our email routing provider (Forward Email) mitigated the issue at around 17:00. We will continue to monitor, but so far the mitigation appears to be successful.

    This issue was due to a third party (Spamhaus) erroneously listing a Forward Email server as a source of spam. Numerous other email systems around the world (including both UIS and Microsoft) trust Spamhaus to identify malicious or compromised systems, and so had started to reject email from that specific Forward Email server, incorrectly believing it to be behaving maliciously. Forward Email have taken the affected server out of rotation until Spamhaus rectifies the issue.

  • Identified
    UTC
    Identified

    We are aware that some mail forwarded through our departmental domains cst.cam.ac.uk and cl.cam.ac.uk is not getting through at the moment. This is particularly affecting mail forwarded to @cam.ac.uk addresses, and is happening due to a problem at our provider. We have contacted the provider and UIS in order to try to resolve this as quickly as possible.

    We believe that most affected mail will get through eventually, once the problem is rectified. There is a chance that some mail will be bounced to its original sender.

    Mail sent directly to @cam.ac.uk addresses is not affected.