Tcpdump is a data-network packet analyzer computer program that runs under a command-line interface. It allows the user to display TCP/IP and other packets being transmitted or received over a network to which the computer is attached. Distributed under the BSD license, tcpdump is free software.
https://www.wireshark.org/
Wireshark is a free and open-source packet analyzer. It is used for network troubleshooting, analysis, software and communications protocol development, and education.
NOTE: Wireshark is very similar to tcpdump, but has a graphical front-end, plus some integrated sorting and filtering options.

Types of Vulnerability Assessment - External Assessment External assessment examines the network from a hacker's point of view to identify exploits and vulnerabilities accessible to the outside world. These types of assessments use external devices such as firewalls, routers, and servers. An external assessment estimates the threat of network security attacks from outside the organization. It determines the level of security of the external network and firewall. (P.527/511) External assessment examines the network from a hacker's point of view to identify exploits and vulnerabilities accessible to the outside world. These types of assessments use external devices such as firewalls, routers, and servers. An external assessment estimates the threat of network security attacks from outside the organization. It determines the level of security of the external network and firewall.
The following are some of the possible steps in performing an external assessment:
o Determine a set of rules for firewall and router configurations for the external network o Check whether the external server devices and network devices are mapped o Identify open ports and related services on the external network o Examine the patch levels on the server and external network devices o Review detection systems such as IDS, firewalls, and application-layer protection systems o Get information on DNS zones o Scan the external network through a variety of proprietary tools available on the Internet o Examine Web applications such as e-commerce and shopping cart software for vulnerabilities

Comprehensive and Detailed Explanation:
LDAP (Lightweight Directory Access Protocol) uses:
* TCP/UDP port 389 for standard LDAP communication.
* TCP/UDP port 636 for secure LDAP over SSL (LDAPS).
From CEH v13 Courseware:
* Module 3: Scanning Networks # Common Ports and Protocols
Incorrect Options:
* A: Port 110 = POP3
* C: Port 464 = Kerberos change/set password
* D: Port 445 = SMB over TCP/IP (used for file sharing)
Reference:CEH v13 Study Guide - Module 3: Well-Known Port NumbersIANA - Service Name and Transport Protocol Port Number Registry

Tautology-based SQL injection tests, such as using ' OR '1'='1, are safe and effective methods to verify whether SQL queries are being manipulated by user input. CEH emphasizes avoiding destructive queries and using logical expressions that return all rows if injection is successful.