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# yum list ettercap\*
Loaded plugins: allowdowngrade, downloadonly, fastestmirror, priorities
Loading mirror speeds from cached hostfile
* elrepo: mirrors.coreix.net
* epel: mirror.vcu.edu
* rpmforge: ftp-stud.fht-esslingen.de
Excluding Packages from RHEL 5 - RPMforge.net - dag
Finished
5266 packages excluded due to repository priority protections
Available Packages
ettercap.x86_64 0.7.3-19.el5 epel
ettercap-common.x86_64 0.7.3-19.el5 epel
ettercap-gtk.x86_64 0.7.3-19.el5 epel
# yum info ettercap
Loaded plugins: allowdowngrade, downloadonly, fastestmirror, priorities
Loading mirror speeds from cached hostfile
* elrepo: mirrors.coreix.net
* epel: mirror.vcu.edu
* rpmforge: ftp-stud.fht-esslingen.de
Excluding Packages from RHEL 5 - RPMforge.net - dag
Finished
5266 packages excluded due to repository priority protections
Available Packages
Name : ettercap
Arch : x86_64
Version : 0.7.3
Release : 19.el5
Size : 209 k
Repo : epel
Summary : Network traffic sniffer/analyser, NCURSES interface version
URL : http://ettercap.sourceforge.net
License : GPL
Description: Ettercap is a suite for man in the middle attacks on LAN. It
: features sniffing of live connections, content filtering on the fly
: and many other interesting tricks. It supports active and passive
: dissection of many protocols (even ciphered ones) and includes many
: feature for network and host analysis.
:
: This package contains the NCURSES version.
Is that the version you installed? Exactly what happens when you attempt to use it?