Recognizing Danger SPAM

Email is enough to help us to communicate and send the news quickly and cheaply, but an email can be a killer application in the world of the Internet, like SMS on the cellular world, extraordinary penetration and almost every Internet user has at least one email address.
The greatness of this email was to invite the parties who want to abuse this email functionality for their own interests, such as spreading viruses and spam.
Spam does not provide direct threats such as damage to computer systems or data such as a virus, but in practice causes tremendous waste of bandwidth and resources in managing this spam. In some cases a spam can cause direct financial loss if combined with phishing activity.

Catch All Account
If your mailserver domain administrator, there is an interesting option that you can do in your mail setting. Catch All. Catch All facilities, all incoming email to your domain will be accepted, whether intended to address valid or invalid addresses.

What is the purpose of activation of this Catch All??
The aim is that all mail addressed to your domain address can be well-received and forwarded to the address specified (generally administratormail address of the server), including the wrong email address or a typo. For example you only have domain name email sales@yourdomain.com, but sometimes sent to subscribers of marketing@yourdomain.com or unconsciously saels@yourdomain.com typo. If you do not activate the Catch All, then the second email to this address you will never accept, for the marketing of this course is a great loss of opportunity so that they will choose to accept all incoming email to the domain.
However, good intentions in the hands of evil people even become a disaster. Once activated Vaksincom Catch All these facilities and consequently, every day of emails received tens of thousands in number and in 3 weeks past the mailbox quota of 2 GB.
After investigation, it turns out it is caused by the account Catch All the swollen and the most ridiculous 99% of incoming email to Catch All the accounts are spam.
Apparently the spammers doing dictionary attack in sending spam. So every time a single domain is active, then the spammers will make a collection of emails to that domain and send the addresses used by a domain and bomb with spam.
For spammers, bandwidth is not a problem because the computer is used to spam other people's computers remotely successfully mastered after a virus infected.

Open Relay
Actually had a lot of work done by antispam companies to overcome the spread of spam, and one of the successful initiatives spam punched with a significant (at the time) is a list of blacklisted mail server.
As we know, is "forbidden" for every mail server maker to open access "open relays for the public" on the mail server because it will be abused by spammers to send spam using that mail server. And once the mail server to send spam and detected by anti-spam company, IP mailserver will be included in the blacklist and not expect your mail to send mail anymore because the other mail server will reject all mail from your mailserver IP unless your mail server IP removed from the blacklist.
This strategy seems effective and not resolved, but unfortunately that the opponents of this anti-spam companies are spammers who are also computer experts, so that spammers and then find a way to defeat this protection. And the bad news, the last few years with how to protect spam blacklist is very decreased effectiveness.

Source : Komputek Ed.663