Information Services

Setting up systems that generate mail

This document explains how systems administrators would configure devices such as computer servers, application software, network attached printers and scanners that can generate email.

End-users should refer to the documentation on configuring mail clients for interactive mail clients such as Outlook, Thunderbird and Apple Mail.

There are two cases that need to be considered:

  1. The device or application has its own on-board mail transport system which accepts mail from the client software and passes it on.
  2. The device or application has no on-board mail transport system.

The device or application has its own on-board mail transport system

This will be the case where the client software generating the mail is configured to use "localhost" or "" as its SMTP relay or smart host. This will be a common setup on linux and other unix-like systems. The machine can be regarded as a "robust" mail sender, and it can connect to

The device or application has no on-board mail transport system.

The client software or service needs to be configured with an external SMTP relay or smart host to submit mail to. This sort of mail sender will generally be "fragile" in that it is incapable of gracefully handling temporary or permanent errors in the mail transport. It needs to connect to the service, which is specially set up to minimise the chances of any such errors. First, though, the IS Unix Section (contact details below) needs to be notified of the connecting address so they can add it to the list of IP addresses which the bulk mail relay will accept mail from.

Configuring correct sender addresses

In either case, the client software must take care to generate with sender addresses that are valid and that accept mail. Mail with invalid sender addresses often fails during transport. Furthermore, non-delivery reports generated by failed messages are returned to the sender address, and if this is not valid or does not accept mail they will end up being sent to the postmaster. They should instead go to someone who is interested in knowing that the mail has failed, and who is in a position to do something about it.

Generally this means that sender addresses should be fixed, valid addresses at one of the usual mail domains:,,,, or some other mail domain associated with a University school or unit. Sender addresses should not be set from user input such as from a field in a web form, as users often get it wrong, though the From: or Reply-To: address may be set this way if the software allows it to be set differently to the sender. It is best to test that mail can be delivered to the sender address before configuring the software to generate mail from that address.

Getting assistance

The Unix Section within Information Services can give assistance on configuring servers, devices and software to correctly send and receive email.

IS ITI Enterprise Services (Unix) Section

  • Unidesk: IS ITI Enterprise Unix

Contact details



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3 Lady Lawson Street

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