1.1 The University’s mail relay service is provided by a set of servers known collectively as oxmail.ox.ac.uk . This system acts in one of two roles:
A mail exchanger is responsible for receiving the mail destined for a mail domain. DNS MX records describe the exchangers linked to each domain. When oxmail acts as an MX it is normally receiving mail from servers outside Oxford.
As much checking as is practical is performed prior to acceptance of a message to maximise the chance of delivery. For mail from outside Oxford, the recipient address is checked with the downstream MTA. The sender address is verified in order to help ensure that in the event of non-delivery after acceptance that an error message can be sent to the sender.
Pre-acceptance checking tries to ensure that all accepted messages are deliverable. Any message that cannot be immediately delivered is queued and further delivery attempts are made from time to time. The retry interval starts small and increases with time. A message will be queued for 7 days before being returned to the sender.
1.9 Messages arriving from outside Oxford are analysed by two methods. All messages are scanned for ‘malware’ by ClamAV software. Any message found to contain malware is rejected after the DATA command. All messages smaller than 150KB are analysed by Spamassassin software to determine a score reflecting the likelihood of the message being ‘spam’. The results of this are recorded in the message headers. Interpretation of this information is left for a downstream process.
2.2 Operator cover is provided from 08:30 to 20:30 on weekdays. Periodic monitoring takes place outside these hours, and informal arrangements exist for staff to be called, but no funding is provided to make this contractual.
2.3 If a fault is notified between 09:00 and 17:00 on a working day, OUCS will commence investigation and correction within one hour (provided that no similar fault is also being handled by the same team).
2.12 Information for departmental and college system administrators is given at http://www.oucs.ox.ac.uk/network/smtp/relay/. Information on the malware and spam scanning procedures is given at http://www.oucs.ox.ac.uk/email/scanning/.
2.13 Notification of faults, outages, etc is circulated on the mailing list email@example.com
3.1 The requirements for University systems to make use of these services are given at http://www.oucs.ox.ac.uk/network/smtp/relay/.