January 17: external ssh access to some Maths systems discontinued, GPU issue in nvidia6 now resolved, all other active Maths servers & services available
January 6th: Unified Access/ZScaler issues: it has come to our notice that Unified Access/ZScaler Connector is not usable from systems connected to a network in a country that is part of the Russian Federation owing to deliberate blocking by ZScaler, the US-based provider of the College's Unified Access service. Users who are within one of these countries who need remote ssh access to Maths internal systems will need to use an ssh gateway but since these are temporarily unavailable externally, please contact Andy Thomas for an interim solution.
December 23rd: external ssh access: owing to the increasing incidence of hostile cyber attacks on publicly-accessible network servers, direct external access via ssh from outside the College to a number of Maths systems has been discontinued over the past few days and today, access to the hessian ssh gateway has also been blocked, in addition to the aachen and cathedral ssh gateways. These systems are those that are less secure for a variety of reasons including a lack of MFA (Multi-Factor Authentication) facilities and/or having more relaxed ssh configurations in order to cater for remote users who can neither use the College's Unified Access (ZScaler Connector) service nor other MFA-capable ssh servers in Maths.
In the case of the hessian ssh gateway, although it does have 2FA authentication as well as support for ssh keypairs, it also deliberately supports users who do not use the latter and instead use typed-in passwords. This latter factor is now considered a security vulnerability and as we begin a two week holiday period with the College officially closed and with very limited central IT support, it has been agreed we discontinue using the more vulnerable systems right at the start.
All staff, research associates, visitors, post-docs and post-graduates are eligible to use the College's Unified Access service which is in effect a VPN (Virtual Private Network) that not only supports ssh connections from outside the College but also other protocols such a web-based services, GUI programming interfaces, etc. To use this you will need to install the ZScaler Client Connector which you can download from here. This supports all the mainstream operating systems and the most popular Linux distributions and is known to work well in practice (note: users of SuSE or openSUSE Linux will find the Red Hat-based version of ZScaler will also work with this Linux distribution).
However, if the operating system you are using is not supported at all by ZScaler, or if you do not have an Imperial College computer account and are using a local Maths external user account which will not work with ZScaler/Unified Access, then you will have to use either of the Maths ssh gateways aachen.ma or cathedral.ma as before. Some Maths compute servers including athena.ma, lovelace.ma and apollo.ma - as well as the share2.ma collaboration server - used to support external users via direct ssh access from outside College, using local Maths user accounts. Since Maths computer accounts are not accepted or supported by the central College Unified Access service, these users will now have to have their local Maths accounts set up on the aachen.ma and cathedral.ma ssh gateways and will then have to visit the College in person to install and set up Google Authenicator 2FA on a smartphone while at the same time using an ssh connection to a non-2FA server on the College's internal network. This way, external users will be able to connect to their Maths user account internally without using 2FA; online documentation will be written over the Christmas break to support these users.
December 16th: nvidia6: one of the 8 GPUs on this GPU server has gone offline - this is not a critical incident but restoring it will mean a server reboot at the very least and possibly downtime if a hardware issue is detected. Given there are 7 other GPUs still functional and in use, resolving this will be postponed for the time being to avoid impacting ongoing users'computations; GPU outages are most often due to simple card crashes owing to excessive loads or GPU memory usage but, occasionally, issues with GPU power cabling arise due to the heavy currents these have to carry to the GPU cards and resolving this type of failure will involve downtime since the server has to be taken out of its rack and be partially dismantled to access the cabling.
December 12th: share2: direct external ssh access to this server, which is used as an access gateway for non-College users to access Maths systems from outside College and for collaboration with Maths users, has now been discontinued as part of the College's drive towards tighter cyber-security. However, external users will instead soon be able to connect via the hessian ssh gateway using Google 2FA multi-factor authentication.
Huxley 616 server room cooling: we are still operating with only three out of four air conditioning units usable since April; replacement of a failed unit in August unhappily coincided with an asbestos survey in the Huxley building which, among other issues in the server room, found one of the working air-con units was contaminated with asbestos and had to be promptly removed and disposed of. Since then it has not been replaced so we are still working within a reduced cooling environment.