April 2005
Intermediate to advanced
344 pages
11h 59m
English
Content preview from Network Security ToolsBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
The find_tcp_conn Plug-in
To
establish a TCP connection with a
remote host, the source host sends a TCP packet with the
SYN
flag set to the remote host. If the
remote host is listening on a particular port, it responds with a TCP
packet with the SYN and
ACK
flags set. The source host then sends
a TCP packet with the ACK bit set to formally
establish the TCP connection. This sequence is known as the
three-way TCP
handshake
. Therefore, to detect new TCP connections
with other hosts, our plug-in has to analyze the network traffic for
TCP packets that have the SYN flag set. The
find_tcp_conn plug-in described in the following
paragraphs analyzes TCP packets for the SYN flag,
and if one is found, it alerts the Ettercap user that a host on the
network is attempting to establish a new TCP connection with another
host.
The find_tcp_conn plug-in alerts the Ettercap user
whenever a TCP packet with the SYN flag set is
captured. Therefore, the plug-in alerts the Ettercap user even if the
server host does not respond to the connection attempt. This plug-in
can be useful for noticing when a SYN port-scan is being performed on a
network.
Warning
The find_tcp_conn plug-in will not detect new TCP
connections when the host running Ettercap is on a network switch
because network switches attempt to segregate network traffic.
Therefore, the find_tcp_conn plug-in will detect SYN packets from other hosts only when the host running Ettercap is on a network hub, or when Ettercap is instructed to perform ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.