The University's message submission service is provided by smtp.ox.ac.uk and can be accessed on either port 587/tcp (recommended) or 25/tcp.
There are two types of access:
SMTP AUTH is available globally and offers GSSAPI, LOGIN and PLAIN authentication types. Use port 587 because many ISPs block outbound 25/tcp traffic. It is unlikely the network you are on will block port 587 but in the event that it does, use the University's central VPN service to tunnel back to the Oxford network so that you can connect to smtp.ox.ac.uk.
Only available to Oxford University IP addresses.
Limits apply to how much mail an individual user or host can send via smtp.ox.ac.uk. IT support staff (ITSS) can submit a service request to apply for frequent heavy users/hosts to have an increased limit.
ITSS are able to view the existing lists of exemptions at the links provided in the posting to ITSS-Announce on 22 June 2020.
The maximum message size accepted is 100 Mbytes.
Alternatively, you may choose to use the message submission service provided by Nexus365.
Explanations of our error messages
Here is a list of error messages given by the University message submission service.
Words beginning with $ are variables which are substituted with applicable values in each message.
Permanent errors result in an SMTP 5xx error code.
Temporary errors result in an SMTP 4xx error code. Depending on your client's SMTP implementation, it may automatically retry after a temporary error.
