107 lines
3.7 KiB
Python
Executable File
107 lines
3.7 KiB
Python
Executable File
#!/usr/bin/env python3
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#
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# Tests the DNS configuration of a Mail-in-a-Box.
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#
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# tests/dns.py ipaddr hostname
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#
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# where ipaddr is the IP address of your Mail-in-a-Box
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# and hostname is the domain name to check the DNS for.
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import sys, re
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import dns.reversename, dns.resolver
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if len(sys.argv) < 3:
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print("Usage: tests/dns.py ipaddress hostname [primary hostname]")
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sys.exit(1)
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ipaddr, hostname = sys.argv[1:3]
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primary_hostname = hostname
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if len(sys.argv) == 4:
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primary_hostname = sys.argv[3]
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def test(server, description):
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tests = [
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(hostname, "A", ipaddr),
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#(hostname, "NS", "ns1.%s.;ns2.%s." % (primary_hostname, primary_hostname)),
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("ns1." + primary_hostname, "A", ipaddr),
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("ns2." + primary_hostname, "A", ipaddr),
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("www." + hostname, "A", ipaddr),
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(hostname, "MX", "10 " + primary_hostname + "."),
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(hostname, "TXT", '"v=spf1 mx -all"'),
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("mail._domainkey." + hostname, "TXT", '"v=DKIM1; k=rsa; s=email; " "p=__KEY__"'),
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#("_adsp._domainkey." + hostname, "TXT", "\"dkim=all\""),
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("_dmarc." + hostname, "TXT", '"v=DMARC1; p=quarantine;"'),
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]
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return test2(tests, server, description)
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def test_ptr(server, description):
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ipaddr_rev = dns.reversename.from_address(ipaddr)
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tests = [
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(ipaddr_rev, "PTR", hostname+'.'),
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]
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return test2(tests, server, description)
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def test2(tests, server, description):
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first = True
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resolver = dns.resolver.get_default_resolver()
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resolver.nameservers = [server]
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for qname, rtype, expected_answer in tests:
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# do the query and format the result as a string
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try:
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response = dns.resolver.resolve(qname, rtype)
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except dns.resolver.NoNameservers:
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# host did not have an answer for this query
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print("Could not connect to %s for DNS query." % server)
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sys.exit(1)
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except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
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# host did not have an answer for this query; not sure what the
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# difference is between the two exceptions
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response = ["[no value]"]
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response = ";".join(str(r) for r in response)
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response = re.sub(r"(\"p=).*(\")", r"\1__KEY__\2", response) # normalize DKIM key
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response = response.replace('"" ', "") # normalize TXT records (DNSSEC signing inserts empty text string components)
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# is it right?
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if response == expected_answer:
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#print(server, ":", qname, rtype, "?", response)
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continue
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# show problem
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if first:
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print("Incorrect DNS Response from", description)
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print()
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print("QUERY ", "RESPONSE ", "CORRECT VALUE", sep='\t')
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first = False
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print((qname + "/" + rtype).ljust(20), response.ljust(12), expected_answer, sep='\t')
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return first # success
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# Test the response from the machine itself.
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if not test(ipaddr, "Mail-in-a-Box"):
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print ()
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print ("Please run the Mail-in-a-Box setup script on %s again." % hostname)
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sys.exit(1)
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else:
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print ("The Mail-in-a-Box provided correct DNS answers.")
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print ()
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# If those settings are OK, also test Google's Public DNS
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# to see if the machine is hooked up to recursive DNS properly.
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if not test("8.8.8.8", "Google Public DNS"):
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print ()
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print ("Check that the nameserver settings for %s are correct at your domain registrar. It may take a few hours for Google Public DNS to update after changes on your Mail-in-a-Box." % hostname)
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sys.exit(1)
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else:
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print ("Your domain registrar or DNS host appears to be configured correctly as well. Public DNS provides the same answers.")
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print ()
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# And if that's OK, also check reverse DNS (the PTR record).
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if not test_ptr("8.8.8.8", "Google Public DNS (Reverse DNS)"):
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print ()
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print (f"The reverse DNS for {hostname} is not correct. Consult your ISP for how to set the reverse DNS (also called the PTR record) for {hostname} to {ipaddr}.")
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sys.exit(1)
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else:
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print ("And the reverse DNS for the domain is correct.")
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print ()
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print ("DNS is OK.")
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