Sender Rewriting Scheme (SRS)

Forwarding email in the modern world

Many mail systems now use the Sender Protection Framework (SPF). This provides protection against phishing attacks. For example, it makes it much harder for an attacker to send a fake email purporting to come from a bank. SPF is now used by all the popular webmail systems to protect their users from such fake emails. This includes gmail, hotmail, outlook, yahoo, and many others. Incoming email that fails their SPF checks will generally be filed as spam, or simply disappear without trace.

SPF does not permit the traditional way of forwarding email, as used by our mail system. This means that if you attempt to forward email from a domain hosted with us to an account at one of the popular webmail sites, it will not arrive reliably.

The Sender Rewriting Scheme (SRS) offers a solution to this problem. It alters the sender address to use your own domain, which means you control the relevant SPF records, and you can ensure that your forwarded email passes SPF checks. We recommend that you publish SPF records for your domains hosted with us.

Hosting account on lynx, onza, and yali

For all our hosting servers except sphinx, SRS can be enabled in the control panel. Simply tick the box “Enable Sender Rewriting Scheme (SRS)” when you create the forwarder on the “Add delivery action” page. Or you can convert an existing forwarder to use SRS by ticking the same box on the “Edit delivery action” page.

Custom exim filter files

If you are using a custom Exim filter file, you can use this command to forward with SRS:

pipe "srs-forward address"

Sphinx accounts

Currently SRS is available on sphinx, but it cannot be configured through the control panel. If you want to set up an SRS-enabled forwarder on sphinx, please email us with the details and we'll be happy to set it up.