diff --git a/ddos-mitigator.sh b/ddos-mitigator.sh
index 43b63b6..22fee09 100755
--- a/ddos-mitigator.sh
+++ b/ddos-mitigator.sh
@@ -38,8 +38,6 @@
 
 # Set the host's own IP address. So far, only an IPv4 address is supported.
 MY_IP="94.199.214.20"
-# Set the desired port to monitor.
-MY_PORT="443"
 
 # After this point, no editing is required.
 start=$(date +%s)
@@ -104,6 +102,9 @@ Usage: $(basename $0) -d FILE [OPTION...]
                          - 3 or 24 for class C networks (X.X.X.0/24)
                          - 4 or 32 for class D networks (X.X.X.X/32)
 
+  -p, --port=PORT        The desired port to monitor.
+                         Defaults to 443 (https).
+
   -h, --help             Show this help message
 
 Mandatory or optional arguments to long options are also mandatory or optional
@@ -130,6 +131,7 @@ function filter() {
 	# subnet suffix, e.g. "/16"
 	suffix="$3"
 	rm -f "${filtered}"
+	touch "${filtered}"
 
 	# Reject already banned addresses
 	while read -r -u3 address ; do
@@ -144,7 +146,7 @@ function filter() {
 }
 
 function parse_command_line_args() {
-	TEMP=$(getopt -o 'a::,c:,d:,j:,n:,h' -l 'auto::,country:,database:,jail:,netmask:,help' -- "$@")
+	TEMP=$(getopt -o 'a::,c:,d:,j:,n:,p:,h' -l 'auto::,country:,database:,jail:,netmask:,port:,help' -- "$@")
 
 	if [ $? -ne 0 ] ; then
 		echo 'Error parsing command line options. Terminating. Invoke with --help for help.' >&2
@@ -204,6 +206,10 @@ function parse_command_line_args() {
 				esac
 				shift
 			;;
+			'-p'|'--port')
+				port="$2"
+				shift
+			;;
 			'-h'|'--help')
 				print_help
 				exit
@@ -388,6 +394,7 @@ netmask=0
 jail="apache-auth"
 bancountry="CN"
 database=
+port=443
 
 parse_command_line_args "$@"
 
@@ -410,7 +417,7 @@ banned="$(exec_as_root fail2ban-client get "${jail}" banip)"
 
 # Determine the current connections to the desired port; store the raw data in
 # $fileraw.
-netstat -nt | grep "${MY_IP}:${MY_PORT}" | tr -s '[:blank:]' | cut -d' ' -f5 \
+netstat -nt | grep "${MY_IP}:${port}" | tr -s '[:blank:]' | cut -d' ' -f5 \
   | cut -d: -f1 | sort > "${fileraw}"
 
 # Group and sort the data into the subnet-specific files.