Comando nmap

Pues, bastante tiempo llevo topándome con el deseo buscar los host que hay en una red desde bash, como son pequeños problemillas al final nunca lo miro. Esta vez lo apunto.

Comando nmap : ver todos los hosts de una red, por ejemplo mi red local de mascara de red de 24 bits.

geus@GeuS-Server:~$ nmap -sP 192.168.1.0/24  at 2006-12-09 08:15 CET

Host 192.168.1.1 appears to be up.
Host 192.168.1.34 appears to be up.
Host 192.168.1.35 appears to be up.

Comando nmap para ver información de los puertos abiertos y el sistema operativo de un host

geus@GeuS-Server:~$ sudo nmap -sS -O 192.168.1.0/24 Starting Nmap 4.10 at 2006-12-09 08:16 CET
WARNING: RST from port 21 — is this port really open?
WARNING: RST from port 21 — is this port really open?
WARNING: RST from port 21 — is this port really open?
WARNING: RST from port 21 — is this port really open?
WARNING: RST from port 21 — is this port really open?
WARNING: RST from port 21 — is this port really open?

Insufficient responses for TCP sequencing (0), OS detection may be less accurate
Interesting ports on 192.168.1.1:
Not shown: 1676 closed ports
PORT STATE SERVICE
21/tcp open ftp
23/tcp open telnet
80/tcp open http

MAC Address: 00:13:49:19:C0:9D (ZyXEL Communications)
Device type: broadband router
Running: ZyXel ZyNOS, Intel embedded
OS details: ZyXel Prestige 791R, ZyXel ZyNOS based Broadband router (ZyNOS) or Intel Express ISDN router