Ever been wondering your ISP is messing with your DNS traffic? Ever observed any misbehavior with your DNS responses? Ever been redirected to wrong address and suspected something is wrong with your DNS? Here we have a set of tools to perform basic tests on your DNS requests and responses.

You can measure the response time of any given DNS server for arbitrary requests using dnsping. Just like traditional ping utility, it gives you similar functionality for DNS requests.

You can also trace the path your DNS request takes to destination to make sure it is not being redirected or hijacked. This can be done by comparing different DNS queries being sent to the same DNS server using dnstraceroute and observe if there is any difference between the path.

dnsperf helps you choose the best DNS server for your network. While it is highly recommended to use your own DNS resolver and never trust any third-party DNS server, but in case you need to choose the best DNS forwarder for your network, dnsperf lets you compare different DNS servers from performance (latency) and reliability (loss) point of view.

prerequisites

This script requires python3 as well as latest dnspython. Please note that "dnstraceroute" requires a modified version of dnspython module, which is included. You just need to run git submodule update --init

dnsping

dnsping pings a DNS resolver by sending an arbitrary DNS query for given number of times:

% ./dnsping.py -c 3 -s 8.8.8.8 -t MX wikipedia.org

DNSPING 8.8.8.8: hostname=wikipedia.org rdatatype=MX
101 bytes from 8.8.8.8: seq=0   time=161.607 ms
101 bytes from 8.8.8.8: seq=1   time=156.355 ms
101 bytes from 8.8.8.8: seq=2   time=145.201 ms

--- 8.8.8.8 dnsping statistics ---
3 requests transmitted, 3 responses received,   0% lost
min=145.201 ms, avg=154.388 ms, max=161.607 ms, stddev=8.378 ms

This script calculates minimum, maximum and average response time as well as jitter

dnsperf

dnsperf is a bulk ping utility that sends an arbitrary DNS query to a give list of DNS servers. This script is meant for comparing response time of multiple DNS servers at once:

% ./dnsperf.py wikipedia.org
server             avg(ms)     min(ms)     max(ms)     stddev(ms)  lost(%)
--------------------------------------------------------------------------
4.2.2.1            151.067     131.270     221.742     28.643      %10
4.2.2.2            142.175     132.921     178.133     13.348      %0
64.6.64.6          133.047     109.145     162.938     20.609      %0
64.6.65.6          377.270     97.669      661.471     172.717     %0
8.8.4.4            389.048     294.581     511.134     67.953      %0
8.8.8.8            0.000       0.000       0.000       0.000       %100
208.67.222.222     179.068     135.975     258.582     50.681      %0
208.67.220.220     137.817     135.822     140.113     1.504       %0

dnstraceroute

dnstraceroute is a traceroute utility to figure out the path that your DNS request is passing through to get to its destination. You may want to compare it to your actual network traceroute and make sure your DNS traffic is not routed to any unwanted path.

% ./dnstraceroute.py -s 4.2.2.1 yahoo.com
 dnstraceroute.py 4.2.2.1: hostname=yahoo.com rdatatype=A
 1       192.168.199.57 (192.168.199.57)  47 ms
 2       192.168.198.21 (192.168.198.21)  21 ms
 3       192.168.169.169 (192.168.169.169)  27 ms
 4       192.168.168.137 (192.168.168.137)  28 ms
 5       so-5-0-0.franco71.fra.seabone.net (89.221.34.6)  23 ms
 6       xe-5-3-1.fra44.ip4.gtt.net (89.149.129.185)  62 ms
 7       *  1126 ms
 8       ae-1-60.edge5.Frankfurt1.Level3.net (4.69.154.9)  62 ms
 9       ae-1-60.edge5.Frankfurt1.Level3.net (4.69.154.9)  12 ms
 10      a.resolvers.level3.net (4.2.2.1)  171 ms