Users are familiar with some network services such as HTTP (Hypertext Transport Protocol) - the Web; and SMTP (Simple Mail Transport Protocol) and POP (Post Office Protocol) - e-mail and instant messaging. But there are others like DHCP (Dynamic Host Configuration Protocol), DNS (Domain Name System), FTP (File Transport Protocol), NNTP (Network News Transport Protocol), Telnet, SSH (Secure Shell), SSL-TLS (Secure Sockets Layer-Transport Layer Security) and others that the average user may not have heard of. 


Tell us more about these services. How do they figure into organizational security? What are the most recent threats against them? What are the risks associated with attacks against network services? What are possible consequences? What are specific controls and general best practices to mitigate risk?