Não sei como eu tinha esquecido disso… mas é uma mão na roda
>: apt-cache show portsentry Package: portsentry Priority: optional Section: universe/net Installed-Size: 284 Maintainer: Ubuntu MOTU Developers <email@example.com> Original-Maintainer: Bruno Barrera C. <firstname.lastname@example.org> Architecture: i386 Version: 1.2-11.1 Depends: libc6 (>= 2.5-0ubuntu1), net-tools, procps, libfile-temp-perl, debconf (>= 1.2.9) | debconf-2.0 Recommends: tcpd Suggests: logcheck Filename: pool/universe/p/portsentry/portsentry_1.2-11.1_i386.deb Size: 71238 MD5sum: 63ab4ce4b105e2c7f9b58c7ac2f8c702 SHA1: b304c1615be5d5c6e72ff1b6e41ec2a27544f0d3 SHA256: 85c1e469ba5263f832e642904f833aac775167356d529d4b2f30333e01caacac Description: Portscan detection daemon PortSentry has the ability to detect portscans(including stealth scans) on the network interfaces of your machine. Upon alarm it can block the attacker via hosts.deny, dropped route or firewall rule. It is part of the Abacus program suite. . Note: If you have no idea what a port/stealth scan is, It's recommended to have a look at http://sf.net/projects/sentrytools/ before installing this package. Otherwise you might easily block hosts you'd better not (e.g. your NFS-server, name-server, etc.).