University of Cambridge Computer Laboratory - Status Page

Internet connectivity disrupted
  • Monitoring
    UTC
    Monitoring

    We observe that internet connectivity appears to be working again at the moment, though we have had no information yet from UIS so cannot guarantee that this will remain the case. The advice to work from home tomorrow still stands for now.

  • Update
    UTC
    Update

    The Departmental Silver Team has decided to recommend that you work from home tomorrow if you can.

  • Update
    UTC
    Update

    Partial connectivity (about 40%) has been restored as of 15:26.

    This remains a University-wide problem but we have had no information from UIS yet.

    If connecting from the internet into our network, only about 40% of our servers will be reachable. If you are unable to connect directly to the system you need, try going via CL VPN1, CL VPN2 or the UIS VPN. If connecting via SSH, you could try connecting via slogin or some other departmental server such as ely.

    Internet connectivity in William Gates Building offices, as well as the rest of the University including eduroam, other departments and colleges, is likely to be barely usable.

    Our main departmental website www.cst.cam.ac.uk remains accessible from the internet as it is hosted outside the University; however pages on www.cl.cam.ac.uk are affected.

  • Update
    UTC
    Update

    We observe that the University is now completely offline. This situation is beyond our control and we await UIS to repair the fault.

  • Identified
    UTC
    Identified

    We are aware that certain hosts within our network are unable to reach certain hosts on the internet.

    (Specifically, any given IP address on our network is unable to reach a different seemingly-random 15% of internet IP addresses.)

    We believe that this may be due to a malfunction or misconfiguration of the University firewall and have contacted the team in UIS responsible for this.

West Cambridge Data Centre major outage 7-22 December
384 hoursScheduled for 07 December, 2026 at 00:00 – 23 December, 2026 at 00:00UTC
  • Planned
    07 December, 2026 at 00:00UTC
    Planned
    07 December, 2026 at 00:00UTC

    UIS are scheduling some major work on the West Cambridge Data Centre during the period 7-22 December 2026, including a 10-day complete electrical outage affecting departmental systems there. This is likely to be highly disruptive to both departmental and University IT. We are considering the impact to our departmental operations and any possible mitigations to keep basic services operational and will update this page when we have more information.

    UIS's announcement follows.

    What is happening? 

    The University is making significant upgrades at the West Cambridge Data Centre to remediate and improve the electrical and cooling works on site. The proposed dates for this work are 7-22 December.

    Why is a full power isolation required?

    This work is required as part of ongoing improvements to the heating and cooling systems on the site. This will both improve resilience for current services, and equip the University to host the Dawn supercomputer, putting us at the forefront of emerging AI technology.

    To complete the work safely, there will need to be a 10-day full power shutdown on the site. There will be additional days in which services will be disrupted while we power down and power up the site. We expect the work be completed within the period 7-22 December 2026.

    Why is it happening at this time?

    This will be a complex and challenging period of work. It is extremely difficult to find a suitable time for an extended power shutdown because the University operates year-round.

    How will this be managed?

    A project team at UIS is coordinating this work. This includes project management, infrastructure and service specialists, technical leads, and communications. Initially, we are working to understand the needs of the services hosted at WCDC and what the impact of the shut down will be. We will seek to mitigate the risks and impact of the shut down as far as is reasonably possible and we will take action to maintain the security and integrity of the site.

100% - uptime

Caelum Console (server management) - Operational

100% - uptime

Request Tracker - Operational

100% - uptime

Other Internal Services - Operational

100% - uptime

External Services - Operational

100% - uptime

Network - Operational

99% - uptime
100% - uptime

GN09 - Operational

100% - uptime

WCDC - Operational

100% - uptime
100% - uptime

Main VM Pool (WCDC) - Operational

100% - uptime

GPUs - Operational

100% - uptime

Secondary VM Hosts - Operational

100% - uptime

Xen Orchestra - Operational

100% - uptime
100% - uptime

Filer - Operational

100% - uptime

Archive Server - Operational

100% - uptime

Data Replication - Operational

100% - uptime

Other Secondary Storage Systems - Operational

100% - uptime
100% - uptime

Third Party: Fastmail → General Availability - Operational

Third Party: Fastmail → Mail delivery - Operational

Third Party: Fastmail → Web client and mobile app - Operational

Third Party: Fastmail → Mail access (IMAP/POP) - Operational

Third Party: Fastmail → Login & sessions - Operational

Third Party: Fastmail → Contacts (CardDAV) - Operational

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