Chip eServices Blog

At Chip eServices as part of our hosted Dynamics CRM offering we are hosting Exchange email for a growing number of customers. Ocassionally we have reported incidents that email fails to deliver because of blacklist (or greylist) filtering on the receiving side.

 A number of companies offer the service of maintaining lists of potentially dangerous servers by IP address or by URL. These lists are called blacklists if communication from the servers (such as email) is intended to be stopped and greylists if communication is to be held for human moderation. If the recipient of the email has either a firewall or an email server that subscribes to these blacklists and you are on one of these blacklists then your email will not be delivered.

 To see if your email address is on a blacklist (or a greylist) you can visit http://www.mxtoolbox.com.

Subscribers to the blacklists can add a URL or IP address to the blacklist. If one subscriber adds you to a blacklist then all other subscribers immediately blacklist you also. Companies that maintain blacklists frequently have agreements to exchange records on their blacklists. Therefore if your email is blacklisted by one company it usually propogates to a number of other blacklist companies also.

Even if you never send SPAM you may inadvertantly find yourself on one or more blacklists. Even if only one email recipient thinks that your email is SPAM they can have you put on a blacklist. To remove yourself from a blacklist you must email the blacklist service provider and ask for removal. As a way of increasing their revenue, some of these companies ask for a fee to have a record removed from a blacklist quickly. If you don’t pay they may take a few days to remove the record.

 If you have problems with your email domain being balcklisted please contact our Network Operations Centre on +353 21 4854300 for support.