The Header and Envelope rewrite mini-HOWTO explains how to rewrite your from address differently in the mail header and the mail envelope. This may be necessary, for example, if your ISP requires you to send mail with one address, but you are subscribed to mailing lists with a different address, or want others to see a forwarding address instead of your ISP's address.
WebTools is "system" of multiple modules and libraries. Along with template engine capabilities, it features session management, global variables support, cookies support, and various database interfaces. It also features a pure Perl mail client, categories management, form checking, and libraries such as a CGI-based downloading library, HTML parsers, and a library that makes PHP functions available to Perl for ease of development.
Hitchhiker's Guide to the Internet is a German introduction to the technical aspects of the Internet. This book explains both the low-level protocols IP, ICMP, TCP, and UDP and the high-level protocols SMTP, POP3, IMAP4, NNTP, HTTP, Gopher, FTP, IRC, DICT, Finger, Daytime, DNS, and Whois.
alph implements and analyzes historical and traditional ciphers and codes, such as polyalphabetic, substitutional, and mixed employing human-reconstructable algorithms. It provides a pipe filter interface in order to encrypt and decrypt block text to achieve transparency. The program is meant to be used in conjunction with external programs that transfer data, resulting in transparent encryption or decryption of information. The program can thus be used as a mail filter, IRC filter, IM filter, and so on.
CryptoCD is a collection of user-friendly documentation for software that provides secure communication through the Internet. The programs cover tasks like email encryption, secure chat, and anonymous Web browsing. CryptoCD comes with comprehensive documentation explaining step by step installation and use of the software for inexperienced users. At the moment, the documentation is only available in German.