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Last active August 28, 2024 00:51
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A DNS propagation checker in Shell Script.
#!/bin/bash
#puck.sh
# A DNS propagation checker. Fetches in many DNS servers around
# the world for IPs assigned to a given domain.
#
# Author: José Lopes de Oliveira Júnior <http://joselop.es>
#
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
#
#TODO: - Add more DNS servers around the world.
#
# Global Variables
#
DOMAIN=""
REGEX="^[a-zA-Z0-9\.-]*(.com|.net|.org|.gov|.br|.es|.uk)$"
# Adding more servers
# The variable which stores IPs uses spaces as
# delimiter. That which stores names uses sem-
# icolons.
#
# Remember that the N'th IP corresponds to the
# N'th name. So, be careful when editing this,
# to avoid mistakes.
SERVERIPS="8.8.8.8 208.67.222.222 68.94.156.1 4.2.2.1 203.23.236.66
202.83.95.227 189.38.95.95 200.221.11.100 202.27.158.40
212.158.248.5 51.255.48.78 151.80.147.153 130.255.73.90
5.135.183.146 202.27.158.40 75.75.75.75 209.18.47.61"
SERVERNAMES="[US] Google Public DNS;[US] OpenDNS;[US] AT&T;[US] Level 3;
[AU] Comcel;[AU] OpenNIC;[BR] GigaDNS;[BR] Universo Online (UOL);
[NZ] Xtra;[UK] Bulldog Broadband; [FR] ns2.als.fr; [FR] ns2.nor.fr; [GER] ns3.nw.de;
[FR] ns12.fr; [NZ] Xtra DNS; [US] Comcast; [US] Time Warner Cable"
USAGE="
USAGE: "${0##*/}" DOMAIN
EXAMPLE
$ ./"${0##*/}" joselop.es
NOTE
DOMAIN MUST be a valid domain like www.joselop.es or
joselop.es. Do NOT use \"http://\" (or something like)
as prefix.
"
#
# Functions
#
main(){
#
# Iterates over IPs list, getting the respective server name and
# checking what is the IP of $DOMAIN in that server.
#
local ip
local name
# Output's header
printf "%-30s %15s\n" " DNS SERVER" "ASSOCIATED IP"
echo " ========================= ==============="
# For each IP, gets its server name,
# updates server name's list and
# figure out the IP for $DOMAIN in
# that DNS server.
for ip in $SERVERIPS; do
name="$(echo $SERVERNAMES | cut -d\; -f1)"
SERVERNAMES="$(echo $SERVERNAMES | cut -d\; -f2-)"
printf "%-30s %15s\n" "$name" "$(answer "$ip" "$DOMAIN")"
done
return $?
}
answer(){
#
# This is the program's core system.
# Receives DNS's IP and Domain through $1 and $2.
# Returns the IP associated to that Domain.
#
dig @"$1" "$2" | grep -a1 "ANSWER SECTION" | tail -1 | awk '{print $NF}'
}
registers(){
#
# Displays all DNS servers used in Puck, with its IP addresses.
#
local ip
local name
# Output's header
printf "%-30s %15s\n" " DNS SERVER" "IP ADDRESS"
echo " ========================= ==============="
for ip in $SERVERIPS; do
name="$(echo $SERVERNAMES | cut -d\; -f1)"
SERVERNAMES="$(echo $SERVERNAMES | cut -d\; -f2-)"
printf "%-30s %15s\n" "$name" "$ip"
done
return $?
}
#
# Main
#
if [ $# -gt "0" ]; then
DOMAIN="$1"
else
echo -n "Domain: "
read -r
DOMAIN="$REPLY"
fi
if [[ $DOMAIN =~ $REGEX ]]; then
if ping -c 1 $DOMAIN > /dev/null 2>&1; then
main
exit $?
else
echo -e "\n$DOMAIN is offline or there is a problem with your link."
echo -e "Check out this issue and try again.\n"
exit 2
fi
else
echo "$USAGE"
exit 1
fi
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