4-2 port banner information acquisition

Classification of ports

Port range 0-65535, yes 2^16

TCP Port and UDP port . because TCP and UDP The two agreements are independent , So their port numbers are also independent of each other , such as TCP Yes 235 port ,UDP There can be 235 port , There is no conflict between the two .

Ports are divided into ：

1、 Known as port

The known port is a well-known port number , Range from 0 To 1023, among 80 Port allocation WWW service 、web service ,21 Port allocation FTP service 、22 Port allocation ssh Service etc. . In this case , When we enter a web address in the address bar of the browser , It is unnecessary to specify the port number , Because by default WWW The port of the service is “80”. if ,HTTP Service changed to 80 port , So at this point , When we input the web address , You need to add... After the colon 8080, Otherwise he will not be able to access , Because he defaults to using 80 port

2、 Dynamic port

Dynamic ports range from 49152 To 65535. It's called dynamic ports , Because it doesn't always allocate certain services , It's dynamic allocation . Therefore, the dynamic port on the computer is listening on , It's probably because of the computer , Controlled by some Trojans , Waiting for the connection

3、 Registered port

port 1024 To 49151, Assign to a user process or application . These processes are mainly user installed programs .

port Banner obtain -nmap

Because each port corresponds to different services , Each service will return different information when we probe , We can use information , Know the current port , Specific services to be opened , And the version number of the service

Use nmap Scan the port information of the specified host , And back to Banner.

nmap IP Address  --script banner -p  Port number 
// We can also specify the range of ports 

After detection , Will be output , Our current port , The corresponding banner Information

ping 192.168.42.236

Test connectivity

nmap 192.168.42.236 -p 22 --script banner
nmap 192.168.42.236 -p 1-65535 --script banner

Some are not open , So there was no return banner Information ,nmap It can be scanned individually , You can also customize multiple ports , Conduct banner Information scanning