As Internet develop and getting more and more important within everyday life network security has become a key issue. Mailing via Internet plays an important role in everyone’s work and private life. Instead of ad papers product advertising moved webpages. On those pages one can not only view, but order the desired items, services. Beside this a lot of personal information is to be found on the Internet.
Network security and protection of servers play an important role in the security these private data. Via electronic mails sensitive data may be reached by unauthorized people. By stopping webpages business activity of the related companies can be disturbed.
This thesis focuses on the importance of the network security issues from the point of Internet service providers. I had a possibility to study how the servers of a business server hosting company are working.
First I introduce how the services work than describe the common forms of attacks then I move to the risks of servers. I describe a real attack against servers via analysing log files. Finally I show the importance and possibilities of prevention.