Linux PortSentry
• portsentry -sudp (”Stealth” UDP scan detection)
• portsentry -audp (Advanced “Stealth” UDP scan detection)
In my case I prefer to start TCP in “Advanced TCP stealth scan detection” protocol mode and UDP in “Stealth UDP scan detection” protocol mode. For information about the other protocol modes, please refer to the “README.install” and “README.stealth” file under the PortSentry source directory.
For TCP mode I choose:
-atcp - Advanced TCP stealth scan detection mode
With the Advanced TCP stealth scan detection mode “-atcp” protocol mode type, PortSentry will first check to see what ports you have running on your server, then remove these ports from monitoring and will begin watching the remaining ports. This is very powerful and reacts exceedingly quickly for port scanners. It also uses very little CPU time.
For UDP mode I choose:
-sudp - “Stealth” UDP scan detection mode
With the Stealth” UDP scan detection mode “-sudp” protocol mode type, the UDP ports will be listed and then monitored.
• To start PortSentry in the two modes selected above, use the commands:
[root@deep /]# /usr/psionic/portsentry/portsentry -atcp
[root@deep /]# /usr/psionic/portsentry/portsentry -sudp
NOTE: You can add the above lines to your 7etc/rc.d/rc.local” script file and PortSentry software will be automatically started if you reboot your system.
Installed files
> /usr/psionic
> /usr/psionic/portsentry
> /usr/psionic/portsentry/portsentry.conf
> /usr/psionic/portsentry/portsentry.ignore
> /usr/psionic/portsentry/portsentry