Ethical Hacking and Network Defense. Network Concepts. Networking Concepts. Network security analyst or security tester must understand networking concepts like TCP/IP (Transmission Control Protocol/Internet Protocol)
You can now enter your e-mail address, which is displayed in the recipient’s From field. You can enter a bogus address, which is how someone can spoof an e-mail, but you should enter your correct e-mail.
Proto Local Address Foreign Address State
TCP 192.168.1.104:49864 MAILHOST-LAB:smtp ESTABLISHED
TCP 192.168.1.104:49865 pz-in-f99:https ESTABLISHED
TCP 192.168.1.104:49866 px-in-f19:https ESTABLISHED
TCP 192.168.1.104:49867 px-in-f97:https ESTABLISHED
The 127 address is used for loopback and testing, no valid for network devices.
You must subtract 2 in the formula because the network portion and host portion of an IP address can’t contain all 1s or all 0s.
Any value in the high-order nibble is multiplied by the number 16. For example, the binary number 0010 0000 is equal to 32. You can multiply the nibble value of 2 by 16, but in this case it’s easier to recognize the 1 in the 32 column, which makes the answer 32.