How does Blacklists work?

An email blacklist or DNS based black hole list is a database which uses a list of criteria to determine whether the IP address sends legitimate emails or spam. Many email servers or ISPs refer such blacklists to get hold of spammers. Since the blacklists have a list of IP address which are found to be spammers or spam friendly servers. If your IP address is being listed in the black list then emails through that IP address will be considered as spam and would not allow your emails to reach subscriber's inbox.

Anyone can create black list and can share that information for the public to use. Not all email blacklists are similar and equal. Each and every blacklist has certain limitations. There are smaller blacklists like SORBS and Spam Cannibal which have less influence with that of bigger ISPs. The large or bigger ISPs use reputable or branded blacklists like SpamCop, Spamhaus and URIBL.

If an IP address or email server gets blacklisted with that of SpamCop then all the emails from that IP address or email server will be blocked by the ISPs which use SpamCop blacklist. But SpamCop have certain limitations and after a certain period of time they usually delist email servers.

For example, a customer might send email campaign to a stale address list. Then if a large percentage of customers report that it to be spam then our IPs will get blacklisted temporarily. This is how it is; one rotten apple is good enough to spoil the entire bunch of apples. Hence MailGoes acts strictly with the "terms of use".

Generally backlists or black hole lists don't just block one IP address of an email server instead get hold of range of IP addresses of that particular email server causing a severe damage to the sender reputation score. This results in blocking the flow of all emails from the entire email server. This could be a serious effect but the spam problem is also a serious issue which needs to be taken care of. Hence if your IP address is being listed in the blacklist, then understand that someone is using your IP range to send spam or someone is a spammer in your IP range. Be alert and be cautious with blacklists.

 

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