CODEWITHSUNDEEP
bashsedawkgrep
exvance
exvance

Reputation: 1439

Bash comprehensive list of IP addresses for a domain

I'm trying to produce a list of all the possible ip addresses for a given domain name. I think I'm close but don't know what I'm missing (or if there is a better way).

First I create a list of variations of the domain like so:

 webkinz.com
 www.webkinz.com

I then loop over this list and run dig on each variation like so:

 while read domain; do
    IPs=`dig $domain | grep $domain | grep -v ';' | awk '{ print $5 }'`;
    echo " ${IPs}" >> /tmp/IPs; #array
 done < /tmp/mylist

 sort -u /tmp/IPs > /tmp/TheIPs; #remove duplicates
 cat /tmp/TheIPs| tr -d "\n" > /tmp/IPs  #remove new lines (making it 1 long line)

My IPs file looks like this:

  66.48.69.100 www.webkinz.com.edgesuite.net.a1339.g.akamai.net.

Only 3 problems. :-(

  1. Dig returned domains when I was only expecting ip addresses.
  2. Some how my script deleted the spaces between the domains.
  3. Some of the ip addresses from dig www.webkinz.com are missing.

So, how should I do this? Do I somehow figure out if dig returned another domain instead of an ip address and run dig on that domain? Do I just ignore domain names returned from dig and figure the ip addresses is sufficient? I want to catch every ip address that will resolve to the domain if possible. I didn't think it should be this hard. Any ideas?

Upvotes: 7

Views: 7867

Answers (4)

Jared Burrows
Jared Burrows

Reputation: 55545

I know this already answered; however, for a list of IPv4 and IPv6 addresses, try this:

Script:

info=$(host google.com); echo "$info" | grep "has address" | awk '{print $4}'; echo "$info" | grep "IPv6" | awk '{print $5}'

host - get the IP addresses
grep - filter the addresses
awk - print the correct strings

script (less lines):

host google.com | awk '/address/ {print $NF}'

Output:

74.125.45.102
74.125.45.113
74.125.45.138
74.125.45.139
74.125.45.100
74.125.45.101
2607:f8b0:4002:c01::8a

Upvotes: 0

Dennis Williamson
Dennis Williamson

Reputation: 360665

In order to get just the IP addresses, use dig +short:

#!/bin/bash
while read -r domain
do
    dig +short "$domain"
done < /tmp/mylist | sort -u | awk '{printf "%s ", $0} END {printf "\n"}' > outputfile

or

#!/bin/bash
echo $(xargs -a /tmp/mylist dig +short | sort -u) > outputfile

Using echo with an unquoted argument drops the newlines except at the end.

You don't need any intermediate variables or temporary files.

Upvotes: 4

musiphil
musiphil

Reputation: 3847

dig gives different types of responses, so it's possible that the fifth column contains domain names. The fifth column will be IP addresses only when the response line is an A response. I would suggest:

dig -t A $domain

instead of

dig $domain

to restrict the type.

Upvotes: 0

dinox0r
dinox0r

Reputation: 16059

Use the following modification in your script to resolve the dns names when is not an ip address

while read domain; do
    IPs=`dig $domain | grep $domain | grep -v ';' | awk '{ print $5 }'`;

    # detect if '$IPs' is an ip address 
    grep "\([0-9]\{1,3\}\.\)\{3\}[0-9]\{1,3\}" <(echo $IPs) >/dev/null 2>&1

    if [ $? -eq 0 ]; then 
        # if IPs is an ip address add it to the file   
        echo " ${IPs}" >> /tmp/IPs; #array          
    else 
        # if not, resolve the domain name using the 'host' command (take just the first line using 'head -1') 
        host $IPs | grep "has address" | head -1 | awk '{ print $4 }' >> /tmp/IPs
    fi

done < mylist

Upvotes: 0

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