Heads up! This site is meant for system operators and other technical staff to find operational notes on Ubivox. Learn more about Ubivox, visit our regular website.


Contacting Ubivox

If you feel that one of our customers has violated our anti-spam policy, you should contact us immediately. You should include all message headers and at least the Message-Id header. Contact the abuse department at:

Ubivox Abuse

If you are an e-mail system operator or have any technical questions regarding our systems and the e-mails coming from them, please contact:

Ubivox Postmaster

Our operations staff responds personally to all e-mails.

What is Ubivox

Ubivox is a Danish e-mail service provider (ESP) founded in 2003 delivering a newsletter management platform consisting of the entire stack from layout and design to databases and delivery.

Learn more about Ubivox  

Anti-spam policy

All customers are bound by our strict anti-spam policy. To give an idea as to what it contains, here is some of the most important points.

We do not tolerate:

  • Mailings to recipients who have not given informed consent to receive communications from our customer.
  • Mailings to recipients that are purchased or rented from a third party.
  • Mailings to recipients who have not been in contact with our customer for more than two years.
  • Mailings to recipients who unsubscribed more than seven days previously.
  • Mailings with content that is not honest and understandable.

Download our full anti-spam policy  

Identification of senders

We only allow verified clients on the system. All clients are manually approved to a specific send limit and we require a verified administrative contact person from all clients.

We always encourage our clients to include as much contact information (address, phone number etc.) as possible in their e-mail for easy identification and we do not allow misleading use of 3rd party contact information.

Technical operation notes

This is a summary on how we operate our outbound mail systems. Both in terms of technologies but also of the configuration of our mail relays. If you have any questions, please let us know.


Since we are sending large volumes of email every day on behalf of many companies, we are always interested in finding the best way to communicate, both for the sender and recipient. If you have any suggestions, which would ease your work in processing and delivering our clients emails for your users, please let us know.

These are the default parameters we use when delivering e-mails from our systems:

  • We will open up to 10 simultaneous connections from each of our SMTP relays.
  • We respect 4xx server greetings and back off if your server indicates it has too much work to do. When encountering a 4xx greeting we will not try again before at least five minutes have passed.

If you are an administrator of a mail server which receives emails sent from Ubivox and feel that the load is affecting your server performance in any way, please do not hesitate to contact us, and we will be very happy to help you.

Outbound SMTP relays

We currently deliver outgoing e-mail from the following systems:

IP address Hostname Role smtp001-ams-lw.ubivox.net Newsletter delivery smtp002-ams-lw.ubivox.net Newsletter delivery smtp003-ams-lw.ubivox.net Newsletter delivery smtp004-ams-lw.ubivox.net Newsletter delivery smtp005-ams-lw.ubivox.net Newsletter delivery smtp006-ams-lw.ubivox.net Newsletter delivery smtp007-ams-lw.ubivox.net Newsletter delivery smtp008-ams-lw.ubivox.net Newsletter delivery smtp009-ams-lw.ubivox.net Newsletter delivery smtp010-ams-lw.ubivox.net Newsletter delivery smtp011-ams-lw.ubivox.net Newsletter delivery smtp012-ams-lw.ubivox.net Newsletter delivery tsmtp001-ams-lw.ubivox.net Transactional emails tsmtp002-ams-lw.ubivox.net Transactional emails vsmtp001-ams-lw.ubivox.net Verified Senders1 vsmtp002-ams-lw.ubivox.net Verified Senders1 vsmtp003-ams-lw.ubivox.net Verified Senders1 vsmtp004-ams-lw.ubivox.net Verified Senders1 qsmtp001-ams-lw.ubivox.net Customer relay qsmtp002-ams-lw.ubivox.net Customer relay qsmtp003-ams-lw.ubivox.net Customer relay qsmtp004-ams-lw.ubivox.net Customer relay csmtp001-ams-lw.ubivox.net Customer relay csmtp002-ams-lw.ubivox.net Customer relay csmtp003-ams-lw.ubivox.net Customer relay csmtp004-ams-lw.ubivox.net Customer relay csmtp005-ams-lw.ubivox.net Customer relay csmtp006-ams-lw.ubivox.net Customer relay csmtp007-ams-lw.ubivox.net Customer relay csmtp008-ams-lw.ubivox.net Customer relay csmtp009-ams-lw.ubivox.net Customer relay csmtp010-ams-lw.ubivox.net Customer relay csmtp011-ams-lw.ubivox.net Customer relay csmtp012-ams-lw.ubivox.net Customer relay csmtp013-ams-lw.ubivox.net Customer relay csmtp014-ams-lw.ubivox.net Customer relay csmtp015-ams-lw.ubivox.net Customer relay csmtp016-ams-lw.ubivox.net Customer relay

1 Verified Sender is a qualification program for those of our customers that goes above best practices and industry standards.

CIDR ranges

The source IP addresses from our outbound SMTP relays can be aggregated to the following CIDR ranges:

  • IPv4

Unsubscribe methods

All newsletters sent from Ubivox contain a List-Unsubscribe header with both an HTTP link and e-mail address that can be used to unsubscribe the recipient from further mailings.

We also require that our clients include a unsubscribe link within the e-mail.

The unsubscription requests are handled automatically and immediately.

Domain Keys Identified Mail

All newsletters sent from Ubivox are DKIM signed with our keys:

  • Key size is at least 1024 bits
  • We only sign using DKIM. We do not use the deprecated Domain Keys protocol.
  • The keys are rotated at least every month.
  • Old keys are removed from DNS within three months.

SPF - Sender Policy Framework

All newsletters and transactional e-mails sent from Ubivox will only originate from relays as indicated by the SPF record of the envelope sender domain name.

Check our SPF records at mxtoolbox.com

Bounce handling

Our systems will collect delivery status notifications regarding soft and hard bounces:

  • Hard bounces (with a 5xx error)
    The subscriber is immediately suspended
  • Soft bounces (with a 4xx error)
    We suspend the subscriber after three consecutive soft bounces of newsletters.

An administrator or subscriber may request to have delivery resumed and we will then lift the suspension and the subscriber will again be subject to the above rules.