Sep 292010
 

ByobuIf you frequently use the terminals and the command line, I hope you know the command screen, otherwise get ready to see something that will help you immensely.

Screen ?

(from the man page)

Screen is a full-screen window manager that multiplexes a physical terminal between several processes (typically interactive shells). Each virtual terminal provides the functions of a DEC VT100 terminal and, in addition, several control functions from the ISO 6429 (ECMA 48, ANSI X3.64) and ISO 2022 standards (e.g. insert/delete line and support for multiple character sets). There is a scrollback history buffer for each virtual terminal and a copy-and-paste mechanism that allows moving text regions between windows.

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Sep 282010
 

NmapLast article of my series on tools for network analysis, after wireshark, ntop and a fine assortment of tools to use with the command line is the time to see nmap.

Nmap (“Network Mapper”) is a free and open source (license) utility for network exploration or security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It was designed to rapidly scan large networks, but works fine against single hosts. Nmap runs on all major computer operating systems, and official binary packages are avalable for Linux, Windows, and Mac OS X. In addition to the classic command-line Nmap executable, the Nmap suite includes an advanced GUI and results viewer (Zenmap), a flexible data transfer, redirection, and debugging tool (Ncat), and a utility for comparing scan results (Ndiff).
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Sep 252010
 

networkAfter ping, telnet and dig we continue to see other useful tools for network analysis done by the command line.

Traceroute

traceroute is a computer network tool used to show the route taken by packets across an Internet Protocol (IP) network. An IPv6 variant, traceroute6, is also widely available.

The traceroute tool is available on practically all Unix-like operating systems. Variants with similar functionality are also available, such as tracepath on modern Linux installations and tracert on Microsoft Windows operating systems. Windows NT-based operating systems also provide PathPing, which provides similar functionality.

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Sep 242010
 

networkIn two previous articles we saw two instruments that have as output of our analysis a graphic form (ntop and wireshark), but today we will see some tools you can use from the command line: Ping, telnet, dig, traceroute, whois, netstat, nmap, and mtr

PING

Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol (IP) network and to measure the round-trip time for messages sent from the originating host to a destination computer. The name comes from active sonar terminology.

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Sep 232010
 

ntopIn the previous article we saw wireshark, which allows, once activated, to capture packets in a given interface, in this article we’ll see ntop software that allows you to have similar information but also something more.

ntop is a network traffic probe that shows the network usage, similar to what the popular top Unix command does. ntop is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform and on Win32 as well.

ntop users can use a web browser (e.g. Firefox) to navigate through ntop (that acts as a web server) traffic information and get a dump of the network status. In the latter case, ntop can be seen as a simple RMON-like agent with an embedded web interface. Continue reading »

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