... services), and of course e-mail servers.4. Protocols used in networks, which many hackers attack. The Internet uses Transmission Control Protocol /Internet Protocol (TCP/IP), which is a fast, efficient, ... withe-mail servers, which include the Simple Mail Transfer Protocol (SMTP), Post Office Protocol 3 (POP3), and the Internet MessageAccess Protocol (IMAP). 5. How applications interact with each ... outages.Although not covered in this book, Cisco Internetworking OperatingSystem (IOS) includes reliability features such as:■Hot Standby Router Protocol (HSRP)■Simple Server Redundancy Protocol (SSRP)■Deterministic...