Spam (also known as “junk” mail) is unsolicited email or newsgroup postings often advertising a product or service. DreamHost makes efforts to prevent users from sending and receiving such email as it results in a variety of different problems for customers and the server.
Spam is sent in various ways and mail servers are always finding new ways to block them. At the same time, spammers find new ways to work around these new roadblocks to get their messages through. So, it’s an ongoing fight to minimize the effect of spam. Some hosts have strict filters, that can result in valid emails getting caught and rejected/discarded, while other hosts may have loose filters that allow more spam in. Finding a balance to this is the challenge.
There is another form of spamming known as “phishing”. Phishing isn’t the same as your standard spam message as it is sent in order to retrieve important information, to sell you a product or sign you up for products/services through fraudulent means. These emails are directed specifically to you, but it is still spam.
Why is spam bad?
Spam is bad for a variety of reasons as it can affect both the users receiving the spam and the servers sending/receiving the spam.
For the recipient of spam mail
It can be aggravating for users to have to go through a large amount of junk mail just to read the valid emails sent to them. This can cause a lot of wasted time sorting through spam finding alternate ways to block it.
Because spam is sent in various ways, certain filtering methods may not work. Because of this, each message may have to be treated individually to find a way to block it.
Junk mail also fills up folders/mailboxes much faster, which can result in your mail user hitting its quota limit. View the Disk Usage Warning article for details.
For the network providers
Spam being sent through a network causes an additional load on the servers that process the data. For example, thousands of incoming spam messages can hit the server at once which may cause slowness and ensuing delivery issues.
Outgoing spam can ruin the sending reputation of a mail server as mail sent is linked to that server’s IP address. This may result in blocks to the IP address which causes further delays and mail delivery failures.
Thus, the issues that affect the server also end up affecting the customer.