ya lo hice pero sigue marcando:
ruby 2.1.5p273 (2014-11-13) [i386-linux-gnu]
Y cuando ejecuto bettercap:
/var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap/spoofers/icmp.rb:24:in `<class:ICMPRedirectPacket>': uninitialized constant PacketFu::EthHeaderMixin (NameError)
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap/spoofers/icmp.rb:17:in `<module:Spoofers>'
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap/spoofers/icmp.rb:15:in `<module:BetterCap>'
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap/spoofers/icmp.rb:14:in `<top (required)>'
from /usr/local/lib/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/lib/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap.rb:66:in `block in bettercap_autoload'
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap.rb:65:in `each'
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap.rb:65:in `bettercap_autoload'
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/lib/bettercap.rb:70:in `<top (required)>'
from /usr/local/lib/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /usr/local/lib/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /var/lib/gems/2.1.0/gems/bettercap-1.5.6b/bin/bettercap:16:in `<top (required)>'
from /usr/local/bin/bettercap:22:in `load'
from /usr/local/bin/bettercap:22:in `<main>'
Que mas puedo hacer?