University of Cambridge Computer Laboratory - University network maintenance: complete internet outage – Maintenance details

UIS have announced network maintenance on 15th-16th July which will result in the entire University having no internet connection for at least an hour starting at 7am on 15th July. They aim to have the work completed by 9am on 15th July but may overrun.

Anyone working locally, for example in their office, will experience disruption, as the internet and cloud services will be inaccessible. Many on-premises systems will also be inaccessible as they rely on cloud services for some functions such as authentication of user accounts. This will affect all wired and wifi connections in the William Gates Building, including eduroam and wgb.

Anyone working remotely and trying to connect to on-premises University services (such as CHRIS, CUFS and any cl.cam.ac.uk system such as filer, slogin or an office computer) will experience disruption, as University servers will be inaccessible from the internet.

Anyone working remotely but only connecting to cloud services (for example, Microsoft applications such as Teams, SharePoint, Office 365, Exchange/Outlook) should not experience any disruption.

The full announcement from UIS follows:

"We will be undertaking work to update and enhance our network service, equipment and security posture on Tuesday 15 July, between 07:00 and 09:00. We’re also reserving 16 July for any additional work we need to complete, but we aim to be finished on 15 July.

There will be some disruption to network connectivity between the University Data Network (UDN) and the internet during this work. Users should plan to avoid critical work on the network during the maintenance period.

This work includes the network maintenance that we postponed in December 2024.

What’s happening

We plan to change the network infrastructure between Janet and the UDN. This will include new border routers, network address translation (NAT) infrastructure, and a replacement for the intrusion prevention system (IPS). This will cause disruption to network connectivity between the UDN and the internet.  

There will be disruption for some users between 07:00 and 09:00 on 15 July, as follows:

• Users working remotely and connecting to cloud services (for example, Microsoft applications such as Teams) should not experience any disruption. 

• Users working remotely and connecting to on-premise University services (such as CHRIS, CUFS) will experience disruption. 

• Users working on the University network (for example, working in the office) will experience disruption to the internet and cloud services.

• Connectivity within the University network, (for example, working in an office and connecting to a University service such as CHRIS) should not experience any disruption.

There will be changes to the way the central NAT service is configured. Read further details about our NAT service.

What you should do 

Users should plan to avoid critical work on the network during 07:00 to 09:00 on the morning of 15 July. This includes hybrid meetings on the University estate. IT officers should advise their users of this disruption. 

We will issue a reminder about this work a week before it is scheduled to take place.

Any issues? 

If you have any queries about this work, please contact the Service Desk."

(Note that for the Department of Computer Science and Technology, the changes to the NAT service only affect eduroam.)