Computer Laboratory

Local System Information

This page offers pointers to detail of how to use lab systems, how to get help, and so on.

Getting help and introductory documents

Administrative matters

Workstation provision

Systems software

Communications and the network

Facilities

If you spot things missing from this page and its sub-pages, please notify sys-admin@cl.cam.ac.uk.

[rss feed]Sys-admin news

18 Jul 2014

Wireless outage

The report I have received from the UIS about today’s wireless outage is slightly inconclusive. It seems that there was a malfunction of the central controller that looks after our access points, causing them to reboot and go into a default unconfigured state. They were initially rescued by moving them to another controller, but have now been put back as they should be without further problems. (more...)

2 Jul 2014

Testing new slogin / ssh-remote server

The main Lab Linux TSS is currently running CentOS 5. We plan to move to Ubuntu Server 14.04 LTS, so have set up a testing server “sandy” (AKA slogin-new and ssh-remote-2.cl.cam.ac.uk). Please try it out and report any problems to sys-admin.

28 Apr 2014

www-dyn(1) upgrade

The server providing the www-dyn1 and www-dyn services is to be upgraded. Users are recommended to check that any pages they publish work on the www-dyn2 and www-dyn3 servers. See http://www.cl.cam.ac.uk/local/web/personal.html#www-dyn for full details.

24 Feb 2014

Further NTP related changes

With the new routers, Lab machines lost the ability to NTP probe machines on the internet, as we lost stateful UDP reflexive rules.
With the recent NTP amplification attacks, we have added rules which mean that machines on the internet cannot NTP probe most Lab machines (our NTP servers should still be accessible).
Peerings (where source and destination ports are both 123) should still work.

18 Jan 2014

Purge of unused VLAN 100 IP addresses

As part of a campaign to clear the use of the original lab subnet, IP address on VLAN 100 in the subnet 128.232.0.0/20 which are believed not to have not been used for a year have been removed from the DNS. Further pruning is likely in future. If you believe an address has been retired but is still needed, please email sys-admin