Network Sniffers

Core Technology

Article from Issue 199/2017
Author(s):

Learn what's going on in your network, using Linux and its arsenal of packet capture tools.

We are always told that eavesdropping is bad. In social relations, that's probably true, but in computing (especially networking) where this activity is known as sniffing, it's an indispensable debugging technique. What goes in the wire is an ultimate answer to "What you've thrown at my service?" and "How did I reply?" Debugging aside, network sniffers may collect statistics or perform security monitoring. Linux comes with many tools of this kind, both GUI and terminal based. In this Core Tech, we'll discover perhaps the most popular one (or just my favorite).

Although sniffing is a legitimate technique, it is still largely prohibited in corporate environments. Many ISPs deem it illegal, too, so be careful when experimenting. A virtual machine based dedicated test lab is the safest option. Anyway, employ common sense and don't sniff traffic that could be sensitive, even if your housemates or colleagues are careless enough to send it unencrypted.

Back to the Beginning

Any network sniffer relies on the operating system's ability to forward it to all packets the network card receives, regardless of which process (or even host) they really target. The exact way of doing this is platform-specific. In Linux, packet sockets are the standard mechanism [1].

[...]

Use Express-Checkout link below to read the full article (PDF).

Buy this article as PDF

Express-Checkout as PDF
Price $2.95
(incl. VAT)

Buy Linux Magazine

SINGLE ISSUES
 
SUBSCRIPTIONS
 
TABLET & SMARTPHONE APPS
Get it on Google Play

US / Canada

Get it on Google Play

UK / Australia

Related content

  • Capture File Filtering with Wireshark

    Wireshark doesn’t just work in real time. If you save a history of network activity in a pcap file using a tool such as tcpdump, you can filter the data with Wireshark to search for evidence.

  • Security Lessons

    Building a network flight recorder with Wireshark.

  • Wireshark

    If you know your way around network protocols, you can get to the source of a problem quickly with Wireshark.

  • Tshark

    The simple and practical Tshark packet analyzer gives precise information about the data streams on the network.

  • Security Visualization Tools

    Spot intruders with these easy security visualization tools.

comments powered by Disqus

Direct Download

Read full article as PDF:

Price $2.95

News