Why are emails that are sent to me, being returned back to sender as SPAM?
Over 90% of emails that are sent around the internet are now spam, which is a major problem for all hosting providers. Therefore the upstream providers we use, run antispam software that use some of the top antispam databases from around the world. This is called an RBL, which stands for Realtime Black List. Most top hosting providers will now use these sorts of RBL antispam systems, which use these same RBL databases. They use IP matching to check what IPs have been sending out spam around the world. This means that anyone who sends you an email, their mailservers IP address that sends the email is checked against this database, to make sure the origin hasn't been used for spamming recently. Using these systems has cut down the number of spam emails being received by the servers considerably.
Someone sending me an email has been blocked? Why?
If a particular email is being blocked by an RBL, it would mean that the provider (usually the ISP) the sender is using, will be blacklisted in one or more RBL databases, very likely because their provider has been reported for sending spam. This is usually due to one of their other customers spamming and abusing the ISPs mailserver, or their customers have Malware on their computer that has hijacked it, and is sending out spam or phishing emails. It could also mean a problem with the senders own computer, and they may have malware installed that is sending out spam emails. The ISP is responsible for managing their own IP addresses, and making sure that they get any blacklists removed, and to make sure none of their customers are sending out spam, or have malware that is sending out spam.
PLEASE NOTE: This is an ISP problem with the person who is sending you the email, as the ISP or email provider of the sender are the ones who have got themselves blacklisted, and need to get the blacklisting removed. It is not a problem at our end. If someone is having trouble sending email to you due to their IP address being blacklisted, that also means they will be having trouble sending to most other people too, as almost all email providers now use some form of RBL. In some cases they may not get a bounced back email, sometimes the email may just automatically go into the recipients spam folder, and they never know about it.
What can I do?
If you have a contact who has been sent an email from our servers, that says their email has been blocked, you will need to ask them to contact their email or ISP provider to get the issue sorted out and the RBL listing removed. You can also refer them to this page for more information. Often the email bounce message the sender receives back, will contain instructions for how to get themselves removed from the blacklist, although not if it is listed on multiple RBLs. Often the sender can follow the instructions in the email and get the blacklist removed, however if the IP continues to send out spam after being removed from the RBL, then it will get blacklisted in the RBL again.Therefore the sender of the email should really contcat their ISP to get the problem fixed, as it is a problem with their email provider.
If the IP is listed on more than one RBL, then it may not contain any further information, apart from saying it is listed on an RBL. However your contact can check to see if the IP has been blacklisted, and which RBLs it is listed on, by entering the IP into the 'Blacklists' section of this website mxtoolbox.com .
The sender of the email can find their IP, by going into the header information of the email they sent, and finding the IP it was sent from, which should look something like this.
Received: from mailserverexample.net.nz (mailserverexample.net.nz [210.70.70.xxx])
If you are not sure how to find the header information, the video below shows you how to do it in outlook 2010.
Other email programs are similar. Please contact your email provider if you are not sure how to find this information. Alternatively you can ask them for the IP of their mailserver to test it. CPanel users can also find the IP for the sender, by using the 'Trace Email' tool inside CPanel, which shows all emails that have been blocked and the IP of the sender..
Usually the blacklist will be removed automatically after a period of time after the spamming problems have been resolved. If the person who has sent you the email are having trouble communicating this problem with the ISP helpdesk staff (who often only have basic knowledge), please ask them to escalate you to the ISPs technicians, and refer them to this webpage.
ISPs will usually eventually solve the problem anyway after a few days, after they have received numerous complaints from other customers with the same problem. However some can be very slow at detecting the problem, and it may not get resolved until they have received many customer complaints about the problem. ISPs however should be monitoring the RBLs to make sure their IPs aren't getting blacklisted, as well as monitoring their systems so they aren't being abused by spammers and malware. Some ISPs are better than others at doing this we have found.
An email provider can also solve the problem instantly for a customer, if they assign a new IP address to send emails from. Alternatively the sender can use a third party SMTP server to send their email through, or use another email account altogether while their email provider fixes the problem.
Some ISPs are constantly getting blacklisted, and they may even recommend to their customer not using their free ISP email services for business use. We would suggest this too, free ISP email addresses are not suitable for business use.
CPanel users can also manage the amount of spam filtering they want, by logging into CPanel and going to the Spam Assassin section. However this won't affect RBL black listings above, as the RBL is an independent filtering system, that is not connected to the servers own built in anti spam systems. More information can be found at http://knowledgebase.loungenetwork.co.nz/index.php?op=view&t=345 CPanel users can also check which email's have been bounced back to the sender, and the reason for the bounce back, by using the 'Trace Email' tool inside CPanel.
So in conclusion, if you have someone sending you an email, and they receive a bounce back to say that their email has been blocked, you will need to ask them to contact their email or ISP provider to get the issue sorted out. It is a problem with the senders email provider, and only their email provider can solve it, as they are the owner of the blacklisted IP. It is not a problem at our end or a problme with your email address.
Being blacklisted in an RBL also means that the sender will be having trouble sending email to most other people too, as most top providers now use the same RBL lists, so it is in their best interests to get their email provider to fix the problem.