Port Scanner for Linux

[danbo]

i have heard that linux (redhat 8.0) has a built in port scanner, is this true ?

if so, how can i access it and scan localhost to see what ports i have open ?

Thankx

[slant6]

The default install includes netstat, which you can use to find out which ports are open, etc. For a more in depth portscanner the most popular is nmap.

[genlee]

netstat isn't really a port scanner. It shows network connections(tcp/udp), nic stats, routing tables, ect for your box. It can show what is listening on each port/ip but only for localhost.

[danbo]

i have executed the command in the terminal :

nmap -sS locahost

and it returns with about 5 ports that are open..... i have my firewall level on high..... am i at risk and if so how can i close these ports ?

and does "BlackICE Defender" work on rehat linux 8.0 ?

[Dolda2000]

Whether or not you are at risk depends on what ports are open. Anyway, netstat is much better for use on the local computer than nmap is. Run netstat -antuwp | egrep "(^[^t])|(^tcp.*LISTEN)" to find out open ports and what programs that are holding them open.

[gokulvadje]

Thanks to all It helped me doing my college assignment