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DNS test: also check a public nameserver to verify that the registrar (or up-host) configuration is correct too

pull/40/head
Joshua Tauberer 9 years ago
parent
commit
95a17a00c0
  1. 88
      tests/dns.py

88
tests/dns.py

@ -1,7 +1,11 @@
#!/usr/bin/python3
# Test DNS configuration.
#
# Tests the DNS configuration of a Mail-in-a-Box.
#
# tests/dns.py ipaddr hostname
#
# where ipaddr is the IP address of your Mail-in-a-Box
# and hostname is the domain name to check the DNS for.
import sys, subprocess, re, difflib
@ -11,48 +15,64 @@ if len(sys.argv) < 3:
ipaddr, hostname = sys.argv[1:]
def dig(digargs):
# construct the expected output
subs = { "ipaddr": ipaddr, "hostname": hostname }
expected = """
{hostname}. ##### IN A {ipaddr}
{hostname}. ##### IN NS ns1.{hostname}.
{hostname}. ##### IN NS ns2.{hostname}.
ns1.{hostname}. ##### IN A {ipaddr}
ns2.{hostname}. ##### IN A {ipaddr}
www.{hostname}. ##### IN A {ipaddr}
{hostname}. ##### IN MX 10 {hostname}.
{hostname}. ##### IN TXT "v=spf1 mx -all"
mail._domainkey.{hostname}. ##### IN TXT "v=DKIM1\; k=rsa\; s=email\; " "p=__KEY__"
""".format(**subs).strip() + "\n"
def dig(server, digargs):
# run dig and clean the output
response = subprocess.check_output(['dig', '@' + ipaddr] + digargs).decode('utf8')
response = subprocess.check_output(['dig', '@' + server, "+noadditional", "+noauthority"] + digargs).decode('utf8')
response = re.sub('[\r\n]+', '\n', response) # remove blank lines
response = re.sub('\n;.*', '', response) # remove comments
response = re.sub('(\n\S+\s+)(\d+)', r'\1#####', response) # normalize TTLs
response = re.sub(r"(\"p=).*(\")", r"\1__KEY__\2", response) # normalize DKIM key
response = response.strip() + "\n"
return response
# call dig a few times with different parameters
digoutput = \
dig([hostname])\
+ dig(["www." + hostname, "+noadditional", "+noauthority"]) \
+ dig(["mx", hostname, "+noadditional", "+noauthority"]) \
+ dig(["txt", hostname, "+noadditional", "+noauthority"]) \
+ dig(["txt", "mail._domainkey." + hostname, "+noadditional", "+noauthority"])
def test(server, description):
# call dig a few times with different parameters
digoutput = \
dig(server, [hostname])\
+ dig(server, ["ns", hostname]) \
+ dig(server, ["ns1." + hostname]) \
+ dig(server, ["ns2." + hostname]) \
+ dig(server, ["www." + hostname]) \
+ dig(server, ["mx", hostname]) \
+ dig(server, ["txt", hostname]) \
+ dig(server, ["txt", "mail._domainkey." + hostname])
# normalize DKIM key
digoutput = re.sub(r"(\"p=).*(\")", r"\1__KEY__\2", digoutput)
# Show a diff if there are any changes
has_diff = False
def split(s): return [line+"\n" for line in s.split("\n")]
for line in difflib.unified_diff(split(expected), split(digoutput), fromfile='expected DNS settings', tofile=description):
if not has_diff:
print("The response from %s (%s) is not correct:" % (description, server))
print()
has_diff = True
# construct the expected output
subs = { "ipaddr": ipaddr, "hostname": hostname }
expected = """
{hostname}. 86400 IN A {ipaddr}
{hostname}. 86400 IN NS ns1.{hostname}.
{hostname}. 86400 IN NS ns2.{hostname}.
ns1.{hostname}. 86400 IN A {ipaddr}
ns2.{hostname}. 86400 IN A {ipaddr}
www.{hostname}. 86400 IN A {ipaddr}
{hostname}. 86400 IN MX 10 {hostname}.
{hostname}. 300 IN TXT "v=spf1 mx -all"
mail._domainkey.{hostname}. 86400 IN TXT "v=DKIM1\; k=rsa\; s=email\; " "p=__KEY__"
""".format(**subs).strip() + "\n"
sys.stdout.write(line)
# Show a diff if there are any changes
has_diff = False
def split(s): return [line+"\n" for line in s.split("\n")]
for line in difflib.unified_diff(split(expected), split(digoutput), fromfile='expected DNS settings', tofile='output from dig'):
sys.stdout.write(line)
has_diff = True
return not has_diff
if not has_diff:
print("DNS is OK.")
sys.exit(0)
# Test the response from the machine itself.
if test(ipaddr, "Mail-in-a-Box"):
# If those settings are OK, also test Google's Public DNS
# to see if the machine is hooked up to recursive DNS properly.
if test("8.8.8.8", "Google Public DNS"):
print ("DNS is OK.")
sys.exit(0)
else:
print ()
print ("Check that the nameserver settings for %s are correct at your domain registrar." % hostname)
sys.exit(1)

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