SWITCHengines Mailgateway

SWITCHengines offers a Mail Gateway Service. By subscribing to the service your virtual machines will be allowed to send e-mails through a secure Mail Gateway which will then relay the e-mails to their final destination. Two servers (one for the Lausanne region and one for the Zurich one) have been installed for redundancy.

To subscribe to the service you can just open a ticket to SWITCHengines (send an email to engines-support@switch.ch) with your request, specifying the public IP addresses of your instances that need to send mail (only Floating IPs (IPv4) and global IPv6 addresses are accepted), and the domains you would like to send e-mails to (it can also be ALL domains).

You will then receive information about the security aspects you should be aware of, after which the request will be processed and your instances will be granted access.

Exim Configuration

As an example of the mail client configuration using exim4 on ubuntu (it can be installed with `apt-get install exim4`):


sudo dpkg-reconfigure exim4-config

on your virtual machine, and in the first screen select the option mail sent by smarthost; no local mail.

In the screen for

IP address or host name of the outgoing smarthost: 



After completing the remaining part of the configuration you will be able to send e-mails through the gateway (after being granted access by the SWITCHengines team).

Postfix Configuration

If you use Postfix, you must specify the relayhost as follow:

relayhost = cloud.switch.ch:587

SMTP Configuration

If you need to configure SMTP manually, specify one of these mail servers as the outgoing mail host. Note that you will not get redundancy in this way.


Use port 587 and TLS encryption. You don't need username/password, as access is controlled via the floating IP of your server.


All outgoing email is scanned for viruses and spam and can and will be deleted if it is either. We reserve the right to block your instances from sending email if we find that the sending service has been compromised and starts to send spam/viruses.

Rate Limiting

We are rate limiting the number of emails you can send per second. If you need to a higher rate limit, contact engines-support@switch.ch