Layer 4

Compare the TCP header to the UDP

tcp header


Discuss ports for TCP and UDP as the ‘addressing’ for layer 4. Referred to as multiplexing in the text.


Compare and contrast uses of UDP vs TCP


Discuss the purpose of DNS

Discuss the structure of DNS


Discuss URL

Discuss SSL


High level overview of Network security threats


Threats to network
Access to Wifi
Infect Laptops
Disgruntled Employees

HAcker Tools
Keystroke Logger


Saved by ASA

Anti-virus: Scans network traffic to prevent the transmission of known viruses based on virus signatures.

Anti-spyware: Scans network traffic to prevent the transmission of spyware programs. Anti-spam: Examines e-mail before it reaches the users, deleting or segregating junk e-mail.
Anti-phishing: Monitors URLs sent in messages through the network, looking for the fake URLs inherent in phishing attacks, preventing the attack from reaching the users.

URL filtering: Filters web traffic based on URL to prevent users from connecting to inappropriate sites.

E-mail filtering: Provides anti-spam tools. Also filters e-mails containing offensive materials, potentially protecting the Enterprise from lawsuits.

Define VPN

Define IDS

Define IPS