Internet Control Message-Protokoll(A required maintenance protocol in the TCP/IP suite that reports errors and allows simple connectivity. ICMP is used by the Ping tool to perform TCP/IP troubleshooting)
Internet Message Access-Protokoll 4(A standard client/server protocol for receiving e-mail. The user (or the user's e-mail client) can view just the heading and the sender of the letter and then decide whether to download the mail)