Find open ports on linux server using a script

Create a .sh file with below script and set execute permission for the scrip file.

#vi portscan.sh


#!/bin/bash
#The port numbers

  • PORT1=21 #ftp
  • PORT2=22 #ssh
  • PORT3=25 #smtp
  • PORT4=53 #dns
  • PORT5=80 #http
  • PORT6=110 #POP3
  • PORT7=143 #IMAP
  • PORT8=443 #https
  • PORT9=1433 #MSSQL
  • PORT10=3306 #MYSQL
  • PORT11=3389 #Microsoft-RDP
  • PORT12=5432 #PostgreSQL

read -p "Enter the Server IP/HOSTNAME : " HOSTNAME #Enter the Host Name to check the Open Ports
echo ""
echo "Checking open/closed ports on the host $HOSTNAME", Please wait….
echo ""
if ping -c2 $HOSTNAME |grep -i "time="
then
echo $HOSTNAME is up
else
echo "$HOSTNAME is down or unable to ping"
fi
echo ""
echo "Checking the port status of $HOSTNAME", Please wait….
echo ""
if nmap -p$PORT1 $HOSTNAME | grep -q open
then
echo $PORT1 is open
else
echo $PORT1 is down
fi
if nmap -p$PORT2 $HOSTNAME | grep -q open
then
echo $PORT2 is open
else
echo $PORT2 is down
fi
if nmap -p$PORT3 $HOSTNAME | grep -q open
then
echo $PORT3 is open
else

 

echo $PORT3 is down
fi
if nmap -p$PORT4 $HOSTNAME | grep -q open
then
echo $PORT4 is open
else
echo $PORT4 is down
fi
if nmap -p$PORT5 $HOSTNAME | grep -q open
then
echo $PORT5 is open
else
echo $PORT5 is down
fi
if nmap -p$PORT6 $HOSTNAME | grep -q open
then
echo $PORT6 is open
else
echo $PORT6 is down
fi
if nmap -p$PORT7 $HOSTNAME | grep -q open
then
echo $PORT7 is open
else
echo $PORT7 is down
fi
if nmap -p$PORT8 $HOSTNAME | grep -q open
then
echo $PORT8 is open
else
echo $PORT8 is down
fi
if nmap -p$PORT9 $HOSTNAME | grep -q open
then
echo $PORT9 is open
else
echo $PORT9 is down
fi
if nmap -p$PORT10 $HOSTNAME | grep -q open
then
echo $PORT10 is open
else
echo $PORT10 is down
fi
if nmap -p$PORT11 $HOSTNAME | grep -q open
then
echo $PORT11 is open
else
echo $PORT11 is down
fi

 

if nmap -p$PORT12 $HOSTNAME | grep -q open
then
echo $PORT12 is open
else
echo $PORT12 is down
fi


# chmod +x portscan.sh

# sh portscan.sh

Enter the Server IP/HOSTNAME : localhost (any server name or ip address)

(You will see the output as below)


Checking open/closed ports on the host localhost, Please wait….

64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.037 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.039 ms
localhost is up

Checking the port status of localhost, Please wait….

  • 21 is down
  • 22 is open
  • 25 is open
  • 53 is down
  • 80 is down
  • 110 is down
  • 143 is down
  • 443 is down
  • 1433 is down
  • 3306 is down
  • 3389 is down