You can find a prebuilt RPM for ettercap in EPEL and wireshark is part of CentOS itself so can be found on the DVD/CD though there is also an updated version available in the CentOS updates repo. You don't say if you are trying to install an RPM from a USB stick or if you are trying to compile from source. Tar zxvf ettercap-0.8.2.tar.gz $ cd ettercap-0.8.2 $ mkdir build $ cd build $ cmake./ $ make $ make install. It supports active and passive dissection of many protocols and includes many features for network and host analysis.
It features sniffing of live connections, content filtering on the fly and many other interesting tricks. Installing ettercap on Linux Ettercap is a comprehensive suite for man in the middle attacks.
