NinerNet Communications™

Corporate Blog

Domains blocked

21 May 2012 14:55:21 +0000

We have taken the unusual step of blocking mail to and from certain domains on our primary mail server that are not (to our knowledge) sources of spam. These domains are:


We have blocked email to these domains because their mail servers — all hosted by the same company — while appearing to be up, do not accept any email. Instead of immediately rejecting email with either permanent (5xx) or temporary (4xx) errors, they hold open the connection from our mail server until it times out. This has a significant negative impact on other email sent by our clients.

Adding to the issue is that the domains associated with the mail servers and nameservers of their hosting provider — and — do not resolve to websites, and the identity of the owner of these domains is hidden behind a WHOIS privacy service. This means that this hosting company does not want to reveal who they are or how to contact them.

We regret the necessity to make this decision, and will revisit it in the future should circumstances change or if new or changed information is brought to light.

As always, please contact NinerNet support should you have any questions or concerns.

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This is the corporate blog of NinerNet Communications. It's where we post announcements, inform and educate our clients, and discuss issues related to the Internet (web and email) hosting business and all it entails. This includes concomitant industries and activities such as domain registration, SSL/TLS certificates, online back-up, virtual private servers (VPS), cloud hosting, etc. Please visit our main website for more information about us.



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