DNSYO is a little tool I built to help me keep track of DNS propagation.
In short, it's
nslookup queried over 1500 servers and collated their results.
Here's what it does
$ dnsyo -t 100 -q ALL example.com Status: Queried 1804 of 1804 servers, duration: 0:00:09.334441 - RESULTS I asked 1804 servers for A records related to example.com, 1771 responded with records and 33 gave errors Here are the results; 1738 servers responded with; 188.8.131.52 26 servers responded with; 127.0.0.1 1 servers responded with; 184.108.40.206 1 servers responded with; 220.127.116.11 1 servers responded with; 18.104.22.168 1 servers responded with; 22.214.171.124 2 servers responded with; 126.96.36.199 1 servers responded with; 188.8.131.52 And here are the errors; 8 servers responded with; No Nameservers 4 servers responded with; No Answer 21 servers responded with; Server Timeout
DNSYO requires Python 2.6 or later. The easiest way to install is by running
pip install dnsyo --upgrade
To install dnsyo on Ubuntu, Debian or Linux Mint:
$ sudo apt-get install python-pip $ sudo pip install dnsyo --upgrade
To install dnsyo on CentOS, Fedora or RHEL:
$ sudo yum install python-pip $ sudo pip install dnsyo --upgrade
You should probably install it within a virtualenv.
If all goes well, you should be clear to start querying stuff
To test, try running
It will query 500 random DNS servers in the database, and give you the results.
For more information on the flags run
DNSYO has 3 output modes;
- standard - Will display all the results and errors from querying
- extended - Same as standard but includes the names and addresses of the servers it queried
- simple - Simple output mode which is useful for UNIX scripting
To change output mode, pass ether
--simple to DNSYO.
DNSYO periodically updates it's internal resolver database from this repo. The first time you run it, and once every 2 weeks, it will try to download the
resolver-list.yml file and store it to
~/.dnsyo-resovers-list.yaml directory. If you know of any more open DNS resolvers feel free to add them to the list.
By default, DNSYO will pick 500 servers at random from it's list to query. You can change this with the
-q flag. If you want DNSYO to query all the servers just pass
dig, you can pass the record type as the second positional argument to DNSYO, so to get Google's MX records just do
dnsyo google.com MX
DNSYO is released under the MIT licence, see
LICENCE.txt for more info
To check DNS lookup results of a domain name:
$ dnsyo xmodulo.com
If you moved your domain name from one IP address to another, and the DNS record has not fully propagated globally, you may see the domain resolved to either IP addresses, depending on which DNS servers are used. In the above example, all responding DNS servers report the same IP address.
Note that many high-traffic websites employ DNS-based load balancing, where domain name is deliberately resolved to a pool of IP addresses. In such cases, a domain name will always be resolved to multiple IP addresses. Check Twitter.com with dnsyo for example:
To get more detailed info of the DNS query (e.g., IP address/location of each DNS server), use "--extended" option.
$ dnsyo --extended xmodulo.com
Using dnsyo, you can also query a specific DNS record type. For example, to find the MX records of Google.com:
dnsyo google.com MX
usage: dnsyo [options] domain [type] Query lots of DNS servers and colate the results positional arguments: domain Domain to query type Record type (A, CNAME, MX, etc.) optional arguments: -h, --help show this help message and exit --resolvlist RESOLVLIST, -l RESOLVLIST Location of the yaml resolvers list to download (http/https) --verbose, -v Extended debug info --simple, -s Simple output mode (good for UNIX parsing) --extended, -x Extended output mode including server addresses --threads THREADS, -t THREADS Number of worker threads to use --servers SERVERS, -q SERVERS Maximum number of servers to query (or ALL) --country COUNTRY, -c COUNTRY Query servers by two letter country code