Linux Common Network Tools: Bulk Host service scanning Nmap

Linux has a lot of powerful network scanning tools, network scanning tools can be divided into: host scanning, host service scanning, route scanning and so on.

Prior to the usual host scan and route scanning tools, NMAP supports bulk host scanning and host service scanning.

Installation of Nmap directly using: Yum install Nmap.

The ICMP scan of Nmap

Nmap can use the ICMP protocol to achieve the PING function, support batch host scan, to detect host survival status.

The TCP protocol does not need to establish three handshakes compared to ICMP, so it is faster, but some firewalls or operators are not scanning for ICMP.

Common commands:

NMAP-SP 192.168.0.1/24

NMAP-SP 192.168.0.*

NMAP-SP 192.168.0.1-255

TCP SYN scan of Nmap

Nmap can scan the open state of a host TCP port by sending a TCP SYN packet to support a TCP semi-open scan.

The SYN scan is faster and less susceptible to detection than the full open scan with three handshake completion.

Nmap scans 1-1024 ports and some other common ports by default, and can be specified with the P option if you want to scan other ports.

Common commands:

Nmap-ss 192.168.2.224nmap-ss 192.168.2.230-255nmap-ss-p 0-30000 192.168.2.230-255

Nmap's TCP Connect scan

Nmap's connect scan is a three-time handshake through TCP, so the speed is slower relative to the SYN half-open scan, but the results are more reliable.

The default scan port and port are specified with the same SYN scan.

Common commands:

Nmap-st 192.168.2.230-255nmap-st-p 0-30000 192.168.2.230-255

Nmap's UDP scan

Nmap also supports the scanning of UDP ports.

UDP is less likely to be blocked by a firewall than the TCP protocol.

Common commands:

Nmap-su 192.168.2.230-255nmap-su-p 0-30000 192.168.2.230-255

Record, for the better of myself!

Linux Common Network Tools: Bulk Host service scanning Nmap