How to Protect Your Network from Spam?

According to the July 2009 edition of the MessageLabs Intelligence Report,Spam remains a major

problem, In fact, it has reached up to 90%, some European countries are higher, up to 95%

Three main problems caused the bad situation.

• The use of automated tools: Spammers are used to use automated tools to
  
  generate email addresses based on domain name.


• URL-shortening spam: Currently, many social networking offers URL-shortening services to
  
  users, 6.2% spamming emails contains shortened URLs to mask unsafe destinations.


• International problem: Unlike we thought the souces of spam emails are outside United
  
  States, According to the static of July, at least, 86% of all e-mails sent in the US are
  
  spam.

Be a network administrator,what can we do to mitigate the effect of spam?

Well, there are two specific network methods you may take.

Traffic management

You'd better to install a network analyzer like Colasoft Capsa network analyzer in your network, that will

help you monitor network traffic especially SMTP traffic we more care

about in this article in real time,Traffic management entails reducing overall message volume by

relying on techniques that are implemented at the protocol level. Essentially,

unwanted senders are identified and their connections dramatically throttled using features that

are inherent to the TCP protocol. This allows incoming volumes of spam to be

slowed, allowing legitimate mail an opportunity to be processed and expedited by the mail

server.

This technique is obviously effective, but it is nevertheless useful to reduce the effect of

a DOS-style of e-mail flooding.

Connection management

Another method would be the use of connection management techniques. An example would be for

incoming SMTP connections from sources known for sending spam and malware to be immediately

rejected. The use of such blacklists can be done at the firewall level and could also include

open proxies or known botnets.

The obvious benefit of connection management is that mail servers do not even have to waste

processor cycles to deal with the incoming spam.

Do you have else methords? let's share our knowledge here!