In this document I plan to explain how to migrate one’s @cam.ac.uk email away from Microsoft Exchange Online (ExOL). As an example of a place to migrate to, I use the SRCF’s Hades system.
The reasons that one might want to migrate away from ExOL are several and varied, and if you are reading this page, you probably already have your own reasons. As a result, I shall not waste my time giving you any more here.
I have written these notes in the hope that they might have been useful to me if I had joined the University after 2018 and had been given ExOL in place of Hermes.
Since I’m not an expert on email, and since I have yet to find myself needing to follow these instructions (and so am unlikely to notice if they go out of date), I’d welcome any corrections at the obvious address. ☺
Email services were (so far as I am aware) first introduced to Cambridge in 1986 on Phoenix, the University Computing Service (UCS)’s IBM mainframe service that ran from 1973–1995.1 UCS then ran the Central Unix Service (CUS) from 1991–2008, on which mail services were also made available. When Phoenix was to be decommissioned, it was decided that a mail system ought to be made available for non-CUS users, especially given the trend of computing away from timesharing to personal workstations. Thus in 1993, the remotely accessible Hermes service was introduced.
When I matriculated in 2016, Hermes remained the default email system for new staff and students, although UIS were making available trial Microsoft Exchange Online (ExOL) accounts. In 2018, new students and staff were given ExOL accounts by default, with new Hermes accounts available for staff that required them. Initially it was promised that Hermes would be retained alongside ExOL for the foreseeable future. In Summer 2020, the decommissioning of Hermes by the end of 2021 was announced, along with the immediate closure of Hermes to new users.
Fearing that Hermes was not long for this world, and wishing to offer new students a standards-compliant email service, the Student-Run Computing Facility (SRCF) launched its Hades email service in 2018. This provides a comparable feature-set to Hermes, including webmail access by Roundcube and Prayer. It also came as an upgrade over their existing shell-server-hosted local mbox-based email service (although there are no plans for this to be decommissioned).
When an email to spqr2@cam.ac.uk reaches the University from the Internet, it will be processed by a set of machines called PPSwitch, whence (following spam checks etc.) it is forwarded to a destination of spqr2’s choosing.
A user can set their choice of destination by altering the ‘@cam delivery address’ field in their Lookup entry. For new users, this will be set to ExOL by default, but forwarding to any address is possible. Many people have their @cam email set to be delivered to a departmental address, their personal address, or (in the case of old users) Hermes.
There is, however, a slight complication for users with existing ExOL accounts. ExOL at Cambridge is configured in such a way that it thinks it runs all of the email @cam.ac.uk. As a result, when ExOL users send mail to @cam.ac.uk addresses, the existence of an ExOL account by that name will cause the message to be delivered there, rather than sent to PPSwitch for delivery to the appropriate address. As a result, such users will have to either continue to check their ExOL mailboxes, separately set them to forward any email out to their chosen address, or just ignore anything sent to them by ExOL users.
So, let’s say you want to avoid ExOL, and have your @cam email sent somewhere else. For the sake of example, I shall use the SRCF’s Hades as a somewhere else in the below instructions. It is a convenient example, as it is a standards-compliant email service which happens to be available to everybody who has an ExOL account. It also gives you an email address with your CRSid as the local part, which is quite handy.
Firstly, If you haven’t yet got an SRCF account, get one here.
By default, email sent to your SRCF address (e.g. spqr2@srcf.net) will be sent to your @cam email address. You can change this in the SRCF control panel so that it is instead delivered to Hades. Note that it is important you point spqr2@srcf.net somewhere other than spqr2@cam.ac.uk before pointing spqr2@cam.ac.uk at spqr2@srcf.net, otherwise you will end up with a loop!
Once you have done this, you might like to verify that mail sent to your SRCF address does indeed end up in your Hades mailbox.
Now alter your Lookup entry so that the ‘@cam delivery address’ field is set to your SRCF address.
Having done this, it is likely that you will want to set ExOL to forward mail that arrives there (see explanation of why this happens above) to your SRCF address. To do this, find the settings in ExOL, then look under Email/Forwarding, and twiddle things appropriately.2 Note that if you subsequently log in to ExOL, you will likely find a notification telling you that forwarding is enabled in the top right hand corner. Be careful if you click on this, as I have heard reports that it is too easy to disable forwarding by doing so. In any case, from this point on you shouldn’t need to look at ExOL ever again.
By this point, mail addressed to your @cam address should end up in your Hades mailbox, irrespective of where it came from. You might now wonder about sending mail and how that will work.
Well, that is very simple. Just set the ‘From’ address to CRSid@cam.ac.uk! Yes, if you are unfamiliar with email, you really can do that. This is generally something that can be set in your email client. There are systems, however, that mean that mail sent from the wrong domain for the from address (e.g. if you were to send mail that said it was from @cam.ac.uk from a gmail account) is less likely to be trusted and accepted by the recipient. In any case, as the SRCF is on the University network, it sends mail out via PPSwitch anyway, so your recipients will (correctly) see your mail has come from the right place.
The way to do this will vary by email client, but since most people apparently use webmail anyway, I’ll explain how one makes the appropriate changes in Hades’ Roundcube webmail interface, from which you will hopefully get a taste for what you might have to look for in other clients. Navigate to the settings, then find the ‘Identities’ tab and click the ‘+’ to add a new one, filling in your @cam address in the ‘Email’ field. If you so desire, there is a toggle to set as your default identity3 when sending mail. To choose the identity for a particular message, simply choose the appropriate entry from the drop-down menu for the ‘From’ field in the composition interface.
At this point we are done, although you might like to move email that you already have in your ExOL mailbox to your Hades mailbox. I am currently unsure of the best way to do this. Ideally, one would access both systems over IMAP and copy things across that way,4 however moving large amounts of mail over IMAP on ExOL has been reported to trigger bugs in ExOL that are regarded as unlikely to be fixed and which result in mail being silently lost. One suggestion I have heard is that one can set up Microsoft Outlook on a computer running Windows/MacOS with both your ExOL account (accessed over some proprietary Microsoft protocol) and your Hades account (accessed over standard IMAP) and copy the mail across that way. I have heard rumours that UIS plan to arrange a way to access ExOL reliably over IMAP, but until then perhaps it is best to ask the UIS for advice as to how to get your mail out of ExOL safely.
Before Phoenix came TITAN, EDSAC 2 and EDSAC.↩︎
These instructions are deliberately vague as I am still a Hermes user and have little interest in keeping up with changes to the ExOL interface. I do have an Alumni ExOL account, but I just have it set to forward to another address.↩︎
That’s the default when sending from Hades Roundcube webmail, not in general when sending from Hades.↩︎