WHY?
– If telnet command is not present on system
– Easy to use
BASH:
ECHO:
#1
echo > /dev/tcp/192.168.0.183/22
#2
echo > /dev/tcp/192.168.0.183/22 && echo "open"
#3
echo > /dev/tcp/192.168.0.183/22 && echo "open" || echo "close"
#4
(echo > /dev/tcp/192.168.0.183/22) > /dev/null 2>&1 && echo "open" || echo "close"
CAT:
cat < /dev/tcp/192.168.0.183/22
CURL:
curl -v telnet://192.168.0.183:22
curl -v telnet://hackfi.initedit.com:80