telnet command is generally used to detect the use of a port, the newly installed linux system or Mac system may not support the telnet command, so we need to install it
1.linux installation:
yum install telnet
2.mac installation need to use a package manager brew
brew install telnet
Linux several common method of communication test port
- 1 telnet method
- 2 wget method
- 3 ssh method
- 4 curl method
1 telnet
# Usage: the Telnet ip Port # (1) the Telnet connection port does not exist in the Telnet 1.1.1.1 8 Trying 1.1.1.1 ... the Telnet: Connect to address 1.1.1.1 : the Timed OUT Connection # (2) the Telnet port link exists the Telnet 8000 1.1.1.1 Trying 1.1.1.1 ... Connected to 1.1.1.1. Escape character is '^]'. Connection closed by foreign host.
2 wget
# Usage: wget ip: Port # (1) there is no port wget 1.1.1.1:8 --2017-01-24 11:38:34-- http://1.1.1.1:8/ Connecting to 1.1.1.1:8... failed: Connection timed out. Retrying. # (2) the presence of port wget 1.1.1.1:8000 --2017-01-24 11:39:03-- http://1.1.1.1:8000/ Connecting to 1.1.1.1:8000... connected. HTTP request sent, awaiting response... 200 OK
3 ssh
# Usage: SSH username @ ip -v -p Port - v debug mode (print journal). - the p-designated port There is no test is given, left to the reader test
4 curl
# Usage: curl IP: Port # (. 1) does not exist port not obtain results # (2) There is a port curl 1.1.1.1:8000 < DOCTYPE HTML!> <HTML > <head > XXX </ head> <body > ...... </body> </html>