Linux Commands & Tools for getting network statistics and port details

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There are many commands available to get network statistics and particular port details. In this article, we are not going in deep to understand these commands but we will just understand the overall functionality of these command.

Nmap Command

Nmap is, especially network exploration tool but it can be used as a security or port scanner. We can scan entire network or selected machine or single server by nmap command. It is also useful for scanning firewall rules.

Nmap is designed to allow system administrators:

·         To scan large networks to determine which servers or hosts are running and what services they are offering. 

·         Nmap supports a large number of scanning techniques such as: UDP, TCP, TCP SYN (half open), ftp proxy (bounce attack), ICMP (ping sweep), FIN,  ACK  sweep,  Xmas Tree, SYN sweep, IP Protocol, and Null scan. 

·         Nmap also offers a number of advanced features such as remote OS detection via TCP/IP fingerprinting, stealth scanning, dynamic delay and retransmission calculations, parallel scanning, detection  of down hosts via parallel pings, decoy scanning, port filtering detection, direct (non-portmapper) RPC scanning, fragmentation scanning, and flexible target and port specification.

Netstat Command

A netstat is a command line tool which provides information about incoming and outgoing network connections, routing tables, network protocol statistics and network interface. Following are some of the features of netstat command.

Features of netstat command:

• Displays routing information maintained by Kernel. (netstat –r)
• Display multicast group membership information.(netstat –g)
• It is displays information related to all network statistics/interfaces. (netstat –s/netstat –i)
• It can monitor system continuously by netstat –tc command. (c – Option most important.)
• It displays the network time related information.

nc Command in Linux (netcat command)

A nc is a command line tool to check TCP and UDP connections and listens it. It can open TCP connections, send UDP packets, listens on TCP and UDP ports, do port scanning and source routing.

Common uses of nc command include:

Ø  Simple TCP proxies
Ø  Shell script based HTTP clients and servers
Ø   Source routing based connectivity testing

Following are some of the best network scanners as :

Unicornscan

Unicornscan is a new information gathering and correlation engine built for and by members of the security research and testing communities. It was designed to provide an engine that is Scalable, Accurate, Flexible, and Efficient. It is released for the community to use under the terms of the GPL license.

Get more information related to this tool by clicking here: unicornscan 

Zenmap – The Network mapper GUI

Zenmap is the Nmap Security Scanner GUI. It is available in multi-platform  for Linux, Windows, Mac OS X, BSD, etc. It is free and open source application and it is designed to make Nmap easy for beginners to use while providing advanced features for experienced Nmap users. Frequently used scans can be saved as profiles to make them easy to run repeatedly. A command creator allows interactive creation of nmap command lines. Scan results can be saved and viewed later. Saved scan results can be compared with one another to see how they differ. The results of recent scans are stored in a searchable database.

Nast – Network Analyzer Sniffer Tool

Nast is a packet sniffer and a LAN analyzer based on Libnet and Libpcap. It can sniff in normal mode or in promiscuous mode the packets on a network interface and log it. It dumps the headers of packets and  the payload in ascii or ascii-hex format. You can apply a filter. The sniffed data can be saved in a parated file.

As analyzer Tool, it has many features like as:

·         Follows a TCP-DATA stream
·         Find LAN Internet gateways
·         Discover promiscuous nodes
·         Reset an established connection
·         Perform a single half-open portscanner
·         Perform a multi half-open portscanner
·         Find link type (hub or switch)
·         Catch daemon banner of LAN nodes
·         Build LAN hosts list

Knocker

Knocker is a simple and easy to use TCP security port scanner written in C to analyze hosts and all of the different services started on them. It is available for Linux, FreeBSD, HP-UX, and Windows9x/2000/NT and it is licensed under the GNU General Public License GPL.

Click here to  know more about Knocker

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