Tutorial Netstat

Valic —  June 29, 2010 — Leave a comment

Netstat (NETwork STATistics) is a command-line tool that provides information about your network configuration and activity.

1. To display the routing table:

#netstat -rn

-r : Kernel routing tables.
-n : Shows numerical addresses instead of trying to determine hosts.

2. To display the quick interfaces statistics:

#netstat -i

-i : Interface

3. To display the extended interfaces statistics:

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Tutorial TCPdump

Valic —  June 28, 2010 — Leave a comment

TCPdump is a very powerful command line interface packetsniffer.

Step 1. Install TCPdump

apt-get install tcpdump

Stept 2. TCPdump use

Step 2.1 To display the Standard TCPdump output:

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
15:14:25.060050 IP > h89-37-110-61.teleson.ro.27005: UDP, length 229
15:14:25.060071 IP > 86-124-241-9.rdsnet.ro.27005: UDP, length 374
15:14:25.060213 IP 86-124-240-65.rdsnet.ro.27005 > UDP, length 78
15:14:25.060236 IP 91-213-135-21.optic-bridge.com.ro.45249 > UDP, length 20
15:14:25.060240 IP > 86-124-240-65.rdsnet.ro.27005: UDP, length 221
15:14:25.060481 IP > 78-21-42-14.access.telenet.be.27005: UDP, length 163
15:14:25.060694 IP > user-ip-23-89-33-89-sel.rdsnav.ro.63087: UDP, length 224
15:14:25.060731 IP > ns1.clax.ro.domain: 65251+ PTR? (43)
15:14:25.060830 IP > UDP, length 113
15:14:25.060851 IP > P 2328008232:2328008428(196) ack 4034406897 win 410
15:14:25.060910 IP > 86-121-72-43.rdsnet.ro.27005: UDP, length 109
15:14:25.060966 IP > UDP, length 74
15:14:25.061020 IP > 95-65-79-185.starnet.md.27005: UDP, length 117

Step 2.2 Network interfaces available for the capture:

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Wget is a free utility for non-interactive download of files from the Web.  It supports HTTP, HTTPS, and FTP protocols, as well as retrieval through HTTP proxies.

Using Wget to download entire website:

Step 1. Create directory where you are planing to store the website content:

mkdir /home/user/offline_site

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Usually, source code are compress in the archive format, its either tar.gz (.tgz) or bz2.

The command uses to extract these archive is tar. Let say your archive is test.2.tar.gz.

You can decompress it and extract to your folder like this:

tar -xzvf xyz2.29.tar.gz -C /usr/src

*-C is to indicate tar where to store the extracted files.

Common open source programs source code comes with configure files and makefiles. Because those programs usually are cross platform compatible. That means it can be compile in different platform such as Unix, Linux, BSD etc, given the required library installed and the dependencies solved. Therefore, before start to compile and install, you usually need to configure.


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vnStat is a console-based network traffic monitor for Linux and BSD that keeps a log of network traffic for the selected interface(s). It uses the network interface statistics provided by the kernel as information source. This means that vnStat won’t actually be sniffing any traffic and also ensures light use of system resources.

Step 1. Installation:

apt-get install vnstat

Step 2. Select the interface you wish to monitor:

for eth0 :

vnstat -u -i eth0

Repeat this changing eth0 for each interface you wish to monitor.

NOTE: Once the text database have been initialised you’re ready to monitor your bandwidth usage. The package installs a cronjob which will update the database every five minutes.

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