The SMTP-Protocol allows the spam distribution in a simple way. This due to the fact that the sender is able to fake its address prior to the dispatch of any e-mail. In order to trace the real address, a sender authentication could represent a possible solution; it would also lead in the direction of a trusted network. Based on this concept only clients which have been authorized by their MTAs are able to send e-mails. This technology was not invented against spam, however the sending of spam would become much more difficult. Initially we analysed the technical causes of spam and its weaknesses on the basis of the SMTP-protocol. Within the second step we have established a market overview, i.e. which protocols are available in which phase of development. Unfortunately, the IETF-working-group MARID (MTA Authorization Records in DNS) has been dissolved in mid September 04, with the consequence that a common standard solution has become at the time being even more unrealistic.

In our practical part we have verified the current and the new measures on their applicability. An additional objective of our undergraduate thesis was to get acquainted with the spammers point of view and his tools involved for sending mass e-mails. Although the original developers claim their programs as legal in view of direct marketing tools, they are more often used for illegal spamming. On the other hand, it also shows that some of the tools can be considered as a positive contribution in view of increasing the security level by disclosing security deficits. The taken measures represent a positive initial start. However this work has to be considered as a process and which has continuously followed up. Without any doubts ?the spammers? will participate continuously with all their efforts and means in their ?race? to develop new ways and solutions enabling them to supply the users with bothering publicity, like spim (spam over instant messaging) and spit (spam ov