Problems sending email to Hotmail addresses

The following information is for customers who may be experiencing problems sending emails to Hotmail users.

Can you send email from Synergy Wholesale servers to Hotmail?

Yes, you can. The problem that a very small number of customers face is when one of our ten outbound spam scanning nodes are blacklisted by Hotmail which then prevents mail from hosting servers connected to that scanning node from getting to Hotmail servers for delivery.

The blacklisting is mostly occurring due to users of Hotmail marking emails as spam from within the Hotmail interface, and from all reports it can take just a single user to mark an email as spam for Hotmail to blacklist the sending server. In many cases we have found our customers have been marking emails as spam in Hotmail that are actually forwarded directly from their web hosting services.

Is this problem happening to any other ISP’s or web hosting providers?

Yes, it is! Our customers have reported issues with Zoho and iiNet when sending to Hotmail addresses, and there are dozens of threads online which show many companies suffering the same problems with Hotmail due to their aggressive spam listings.

What are Synergy Wholesale doing to solve this problem?

Over the past twelve months we have made many changes and improvements to help clean up spam originating from our infrastructure, not only because of Hotmail but other blacklistings from more reliable sources. In a shared web hosting environment it is an impossible task to completely eliminate spam but we have made serious progress by:

• Deploying a cluster of SpamExperts outbound scanning nodes that check every message sent from our shared hosting fleet for spam and viruses before it attempts to deliver it to the recipient. The benefit of deploying this system is that it has allowed us to not only catch spam before it leave our network which prevents our servers from being blacklisted, but it also gives us the information we need to quickly identify the source of the spam and shut it down.
• Following on from the above point, our development team created an automated system that would feed the information supplied by the spam scanning cluster and take appropriate action based on certain limits that we created.
• Deploying CXS across every server in our fleet which assists in removing compromised files before they can be used to send spam.
• Making tweaks and changes to our spam scanning cluster which will involve adding new scanning nodes to further dilute the impact of scanning nodes being blacklisted, adding new IP addresses from different ranges to allow for better rotation capabilities, and some other changes recommended to us by cPanel and SpamExperts.

In the image below you can see a current (as at 28/11/15) snapshot of our scanning node reputations:

IP addresses that are currently listed (shown in red) are not in use and will remain inactive until de-listing has been completed. This proves that sending email to virtually any email provider in the world will not have an issue from Synergy Wholesale hosting servers.

Other web hosting providers are saying they have a better system and it doesn’t happen to them?

Good for them. 😉

It’s almost a certainty that it in fact does happen to them from time to time, and we have observed a number of social media posts from other providers claiming to have custom-built solutions which somehow makes it better than everybody else, including our system that is deployed, managed and supported by SpamExperts.

Let’s stick to the facts:

• Almost every linux-based spam scanning system is based in whole or in part on MailScanner and/or Spamassassin with ClamAV. So the capability to detect and remove spam is pretty much the same across the board.
• The difference with SpamExperts is having the intelligence being sourced from hundreds of implementations across the world which are constantly tracking, learning and reporting spam and virus signatures that are subsequently vetted and passed back to the scanning nodes in addition to those obtained from Spamassassin and ClamAV.

But we all know that when things work it’s a great day, but what happens when something goes wrong with it?

If you’re relying on a custom-built solution that is based off of a bunch of open source applications then your support options are strictly limited to the know-how of your administrators or Googling for others who many have experienced the same issue in the past and have blogged about it. When you’re talking about using this service for paying customers we simply don’t agree that this is an acceptable level of risk and our own internal testing proved this.

Before selecting SpamExperts for our outbound spam scanning platform we evaluated a number of different solutions which included a custom-built system which used the above mentioned applications and Baruwa Enterprise Edition.

The custom-built solution seemed to work until random issues would introduce themselves through bad updates and later broken dependencies between the individual systems began to appear. There was also no central view or control which severely restricted our ability to monitor issues and meant changes made to one node had to then be made manually across the other nodes.

Baruwa Enterprise Edition, which by their own admission is a front end for MailScanner, was tested and subsequently deployed in our live environment for a number of weeks until one day when it suddenly stopped working. Attempts to get support resulted in their suggestion of re-installing and starting again.

This lead us to turn to SpamExperts who we already used for our inbound spam scanning nodes, allowing us to temporarily use our inbound scanning nodes as trial outbound scanning nodes. Within hours of pointing a handful of our hosting servers to the outbound scanning nodes we had a full view of the spam being sent by these servers and the services responsible which allowed us to take immediate action.

After weeks of successful trials we went ahead with full implementation that was completed by the SpamExperts team. Any issues were quickly resolved and after nearly twelve months of successful use we are very pleased with the decision we made.

Conclusion (tl;dr)

The fighting of spam is an ongoing problem for every online service company in the world and it will continue to be a battle while ever systems are connected to the internet with access to SMTP.

Issues with sending email to Hotmail are a rare occurrence and generally affect a very small number of our customer base at any one time (if at all).

Synergy Wholesale in conjunction with SpamExperts will continue to make the changes needed to get our platform as close to perfect as possible. We will continue to actively monitor blacklisting events and take the appropriate action as quickly as possible.

If you experience an issue with email not making it to the intended destination, please contact our support team through the Synergy Wholesale management system and provide as much information as possible so it can be investigated for you.