Fixed IPv6 parsing

management/ssl_certificates.py

@@ -256,6 +256,7 @@ def get_certificates_to_provision(env, show_extended_problems=True, force_domain
 
 			if len(response) != 1 or rdata__str__(response[0]) != value:
 				problems[domain] = "Domain control validation cannot be performed for this domain because DNS points the domain to another machine (%s %s)." % (rtype, ", ".join(rdata__str__(r) for r in response))
+				print(value)
 				return False
 
 		return True

management/status_checks.py

@@ -430,7 +430,7 @@ def check_primary_hostname_dns(domain, env, output, dns_domains, dns_zonefiles):
 	else:
 		output.print_error("""The DANE TLSA record for incoming mail (%s) is not correct. It is '%s' but it should be '%s'.
 			It may take several hours for public DNS to update after a change."""
-						% (tlsa_qname, tlsa25, tlsa25_expected))
+                        % (tlsa_qname, tlsa25, tlsa25_expected))
 
 	# Check that the hostmaster@ email address exists.
 	check_alias_exists("Hostmaster contact address", "hostmaster@" + domain, env, output)
@@ -703,9 +703,9 @@ def query_dns(qname, rtype, nxdomain='[Not Set]', at=None):
 	for r in response:
 		s = r.to_text()
 		if isinstance(s, bytes):
-			 s = s.decode('utf-8')
-		s = str(ipaddress.ip_address(s))
+			s = s.decode('utf-8')
 		response_new.append(s)
+	
 	response = response_new
 	# END HOTFIX
 

management/status_checks.py.bak

@@ -0,0 +1,990 @@
+#!/usr/bin/python3
+# coding=utf-8
+#
+# Checks that the upstream DNS has been set correctly and that
+# TLS certificates have been signed, etc., and if not tells the user
+# what to do next.
+
+import sys, os, os.path, re, subprocess, datetime, multiprocessing.pool
+
+import dns.reversename, dns.resolver
+import dateutil.parser, dateutil.tz
+import idna
+import psutil
+import ipaddress
+
+from dns_update import get_dns_zones, build_tlsa_record, get_custom_dns_config, get_secondary_dns, get_custom_dns_records
+from web_update import get_web_domains, get_domains_with_a_records
+from ssl_certificates import get_ssl_certificates, get_domain_ssl_files, check_certificate
+from mailconfig import get_mail_domains, get_mail_aliases
+
+from utils import shell, sort_domains, load_env_vars_from_file, load_settings
+
+def get_services():
+	return [
+		{ "name": "Local DNS (bind9)", "port": 53, "public": False, },
+		#{ "name": "NSD Control", "port": 8952, "public": False, },
+		{ "name": "Local DNS Control (bind9/rndc)", "port": 953, "public": False, },
+		{ "name": "Dovecot LMTP LDA", "port": 10026, "public": False, },
+		{ "name": "Postgrey", "port": 10023, "public": False, },
+		{ "name": "Spamassassin", "port": 10025, "public": False, },
+		{ "name": "OpenDKIM", "port": 8891, "public": False, },
+		{ "name": "OpenDMARC", "port": 8893, "public": False, },
+		{ "name": "Memcached", "port": 11211, "public": False, },
+		{ "name": "Mail-in-a-Box Management Daemon", "port": 10222, "public": False, },
+		{ "name": "SSH Login (ssh)", "port": get_ssh_port(), "public": True, },
+		{ "name": "Public DNS (nsd4)", "port": 53, "public": True, },
+		{ "name": "Incoming Mail (SMTP/postfix)", "port": 25, "public": True, },
+		{ "name": "Outgoing Mail (SMTP 587/postfix)", "port": 587, "public": True, },
+		#{ "name": "Postfix/master", "port": 10587, "public": True, },
+		{ "name": "IMAPS (dovecot)", "port": 993, "public": True, },
+		{ "name": "Mail Filters (Sieve/dovecot)", "port": 4190, "public": True, },
+		{ "name": "HTTP Web (nginx)", "port": 80, "public": True, },
+		{ "name": "HTTPS Web (nginx)", "port": 443, "public": True, },
+	]
+
+def run_checks(rounded_values, env, output, pool):
+	# run systems checks
+	output.add_heading("System")
+
+	# check that services are running
+	if not run_services_checks(env, output, pool):
+		# If critical services are not running, stop. If bind9 isn't running,
+		# all later DNS checks will timeout and that will take forever to
+		# go through, and if running over the web will cause a fastcgi timeout.
+		return
+
+	# clear bind9's DNS cache so our DNS checks are up to date
+	# (ignore errors; if bind9/rndc isn't running we'd already report
+	# that in run_services checks.)
+	shell('check_call', ["/usr/sbin/rndc", "flush"], trap=True)
+
+	run_system_checks(rounded_values, env, output)
+
+	# perform other checks asynchronously
+
+	run_network_checks(env, output)
+	run_domain_checks(rounded_values, env, output, pool)
+
+def get_ssh_port():
+	# Returns ssh port
+	try:
+		output = shell('check_output', ['sshd', '-T'])
+	except FileNotFoundError:
+		# sshd is not installed. That's ok.
+		return None
+
+	returnNext = False
+	for e in output.split():
+		if returnNext:
+			return int(e)
+		if e == "port":
+			returnNext = True
+
+	# Did not find port!
+	return None
+
+def run_services_checks(env, output, pool):
+	# Check that system services are running.
+	all_running = True
+	fatal = False
+	ret = pool.starmap(check_service, ((i, service, env) for i, service in enumerate(get_services())), chunksize=1)
+	for i, running, fatal2, output2 in sorted(ret):
+		if output2 is None: continue # skip check (e.g. no port was set, e.g. no sshd)
+		all_running = all_running and running
+		fatal = fatal or fatal2
+		output2.playback(output)
+
+	if all_running:
+		output.print_ok("All system services are running.")
+
+	return not fatal
+
+def check_service(i, service, env):
+	if not service["port"]:
+		# Skip check (no port, e.g. no sshd).
+		return (i, None, None, None)
+
+	output = BufferedOutput()
+	running = False
+	fatal = False
+
+	# Helper function to make a connection to the service, since we try
+	# up to three ways (localhost, IPv4 address, IPv6 address).
+	def try_connect(ip):
+		# Connect to the given IP address on the service's port with a one-second timeout.
+		import socket
+		s = socket.socket(socket.AF_INET if ":" not in ip else socket.AF_INET6, socket.SOCK_STREAM)
+		s.settimeout(1)
+		try:
+			s.connect((ip, service["port"]))
+			return True
+		except OSError as e:
+			# timed out or some other odd error
+			return False
+		finally:
+			s.close()
+
+	if service["public"]:
+		# Service should be publicly accessible.
+		if try_connect(env["PUBLIC_IP"]):
+			# IPv4 ok.
+			if not env.get("PUBLIC_IPV6") or service.get("ipv6") is False or try_connect(env["PUBLIC_IPV6"]):
+				# No IPv6, or service isn't meant to run on IPv6, or IPv6 is good.
+				running = True
+
+			# IPv4 ok but IPv6 failed. Try the PRIVATE_IPV6 address to see if the service is bound to the interface.
+			elif service["port"] != 53 and try_connect(env["PRIVATE_IPV6"]):
+				output.print_error("%s is running (and available over IPv4 and the local IPv6 address), but it is not publicly accessible at %s:%d." % (service['name'], env['PUBLIC_IP'], service['port']))
+			else:
+				output.print_error("%s is running and available over IPv4 but is not accessible over IPv6 at %s port %d." % (service['name'], env['PUBLIC_IPV6'], service['port']))
+
+		# IPv4 failed. Try the private IP to see if the service is running but not accessible (except DNS because a different service runs on the private IP).
+		elif service["port"] != 53 and try_connect("127.0.0.1"):
+			output.print_error("%s is running but is not publicly accessible at %s:%d." % (service['name'], env['PUBLIC_IP'], service['port']))
+		else:
+			output.print_error("%s is not running (port %d)." % (service['name'], service['port']))
+
+		# Why is nginx not running?
+		if not running and service["port"] in (80, 443):
+			output.print_line(shell('check_output', ['nginx', '-t'], capture_stderr=True, trap=True)[1].strip())
+
+	else:
+		# Service should be running locally.
+		if try_connect("127.0.0.1"):
+			running = True
+		else:
+			output.print_error("%s is not running (port %d)." % (service['name'], service['port']))
+
+	# Flag if local DNS is not running.
+	if not running and service["port"] == 53 and service["public"] == False:
+		fatal = True
+
+	return (i, running, fatal, output)
+
+def run_system_checks(rounded_values, env, output):
+	check_ssh_password(env, output)
+	check_software_updates(env, output)
+	check_miab_version(env, output)
+	check_system_aliases(env, output)
+	check_free_disk_space(rounded_values, env, output)
+	check_free_memory(rounded_values, env, output)
+
+def check_ufw(env, output):
+	if not os.path.isfile('/usr/sbin/ufw'):
+		output.print_warning("""The ufw program was not installed. If your system is able to run iptables, rerun the setup.""")
+		return
+
+	code, ufw = shell('check_output', ['ufw', 'status'], trap=True)
+
+	if code != 0:
+		# The command failed, it's safe to say the firewall is disabled
+		output.print_warning("""The firewall is not working on this machine. An error was received
+					while trying to check the firewall. To investigate run 'sudo ufw status'.""")
+		return
+
+	ufw = ufw.splitlines()
+	if ufw[0] == "Status: active":
+		not_allowed_ports = 0
+		for service in get_services():
+			if service["public"] and not is_port_allowed(ufw, service["port"]):
+				not_allowed_ports += 1
+				output.print_error("Port %s (%s) should be allowed in the firewall, please re-run the setup." % (service["port"], service["name"]))
+
+		if not_allowed_ports == 0:
+			output.print_ok("Firewall is active.")
+	else:
+		output.print_warning("""The firewall is disabled on this machine. This might be because the system
+			is protected by an external firewall. We can't protect the system against bruteforce attacks
+			without the local firewall active. Connect to the system via ssh and try to run: ufw enable.""")
+
+def is_port_allowed(ufw, port):
+	return any(re.match(str(port) +"[/ \t].*", item) for item in ufw)
+
+def check_ssh_password(env, output):
+	# Check that SSH login with password is disabled. The openssh-server
+	# package may not be installed so check that before trying to access
+	# the configuration file.
+	if not os.path.exists("/etc/ssh/sshd_config"):
+		return
+	sshd = open("/etc/ssh/sshd_config").read()
+	if re.search("\nPasswordAuthentication\s+yes", sshd) \
+		or not re.search("\nPasswordAuthentication\s+no", sshd):
+		output.print_error("""The SSH server on this machine permits password-based login. A more secure
+			way to log in is using a public key. Add your SSH public key to $HOME/.ssh/authorized_keys, check
+			that you can log in without a password, set the option 'PasswordAuthentication no' in
+			/etc/ssh/sshd_config, and then restart the openssh via 'sudo service ssh restart'.""")
+	else:
+		output.print_ok("SSH disallows password-based login.")
+
+def is_reboot_needed_due_to_package_installation():
+	return os.path.exists("/var/run/reboot-required")
+
+def check_software_updates(env, output):
+	# Check for any software package updates.
+	pkgs = list_apt_updates(apt_update=False)
+	if is_reboot_needed_due_to_package_installation():
+		output.print_error("System updates have been installed and a reboot of the machine is required.")
+	elif len(pkgs) == 0:
+		output.print_ok("System software is up to date.")
+	else:
+		output.print_error("There are %d software packages that can be updated." % len(pkgs))
+		for p in pkgs:
+			output.print_line("%s (%s)" % (p["package"], p["version"]))
+
+def check_system_aliases(env, output):
+	# Check that the administrator alias exists since that's where all
+	# admin email is automatically directed.
+	check_alias_exists("System administrator address", "administrator@" + env['PRIMARY_HOSTNAME'], env, output)
+
+def check_free_disk_space(rounded_values, env, output):
+	# Check free disk space.
+	st = os.statvfs(env['STORAGE_ROOT'])
+	bytes_total = st.f_blocks * st.f_frsize
+	bytes_free = st.f_bavail * st.f_frsize
+	disk_msg = "The disk has %.2f GB space remaining." % (bytes_free/1024.0/1024.0/1024.0)
+	if bytes_free > .3 * bytes_total:
+		if rounded_values: disk_msg = "The disk has more than 30% free space."
+		output.print_ok(disk_msg)
+	elif bytes_free > .15 * bytes_total:
+		if rounded_values: disk_msg = "The disk has less than 30% free space."
+		output.print_warning(disk_msg)
+	else:
+		if rounded_values: disk_msg = "The disk has less than 15% free space."
+		output.print_error(disk_msg)
+
+def check_free_memory(rounded_values, env, output):
+	# Check free memory.
+	percent_free = 100 - psutil.virtual_memory().percent
+	memory_msg = "System memory is %s%% free." % str(round(percent_free))
+	if percent_free >= 20:
+		if rounded_values: memory_msg = "System free memory is at least 20%."
+		output.print_ok(memory_msg)
+	elif percent_free >= 10:
+		if rounded_values: memory_msg = "System free memory is below 20%."
+		output.print_warning(memory_msg)
+	else:
+		if rounded_values: memory_msg = "System free memory is below 10%."
+		output.print_error(memory_msg)
+
+def run_network_checks(env, output):
+	# Also see setup/network-checks.sh.
+
+	output.add_heading("Network")
+
+	check_ufw(env, output)
+
+	# Stop if we cannot make an outbound connection on port 25. Many residential
+	# networks block outbound port 25 to prevent their network from sending spam.
+	# See if we can reach one of Google's MTAs with a 5-second timeout.
+	code, ret = shell("check_call", ["/bin/nc", "-z", "-w5", "aspmx.l.google.com", "25"], trap=True)
+	if ret == 0:
+		output.print_ok("Outbound mail (SMTP port 25) is not blocked.")
+	else:
+		output.print_error("""Outbound mail (SMTP port 25) seems to be blocked by your network. You
+			will not be able to send any mail. Many residential networks block port 25 to prevent hijacked
+			machines from being able to send spam. A quick connection test to Google's mail server on port 25
+			failed.""")
+
+	# Stop if the IPv4 address is listed in the ZEN Spamhaus Block List.
+	# The user might have ended up on an IP address that was previously in use
+	# by a spammer, or the user may be deploying on a residential network. We
+	# will not be able to reliably send mail in these cases.
+	rev_ip4 = ".".join(reversed(env['PUBLIC_IP'].split('.')))
+	zen = query_dns(rev_ip4+'.zen.spamhaus.org', 'A', nxdomain=None)
+	if zen is None:
+		output.print_ok("IP address is not blacklisted by zen.spamhaus.org.")
+	else:
+		output.print_error("""The IP address of this machine %s is listed in the Spamhaus Block List (code %s),
+			which may prevent recipients from receiving your email. See http://www.spamhaus.org/query/ip/%s."""
+			% (env['PUBLIC_IP'], zen, env['PUBLIC_IP']))
+
+def run_domain_checks(rounded_time, env, output, pool):
+	# Get the list of domains we handle mail for.
+	mail_domains = get_mail_domains(env)
+
+	# Get the list of domains we serve DNS zones for (i.e. does not include subdomains).
+	dns_zonefiles = dict(get_dns_zones(env))
+	dns_domains = set(dns_zonefiles)
+
+	# Get the list of domains we serve HTTPS for.
+	web_domains = set(get_web_domains(env))
+
+	domains_to_check = mail_domains | dns_domains | web_domains
+
+	# Get the list of domains that we don't serve web for because of a custom CNAME/A record.
+	domains_with_a_records = get_domains_with_a_records(env)
+
+	# Serial version:
+	#for domain in sort_domains(domains_to_check, env):
+	#	run_domain_checks_on_domain(domain, rounded_time, env, dns_domains, dns_zonefiles, mail_domains, web_domains)
+
+	# Parallelize the checks across a worker pool.
+	args = ((domain, rounded_time, env, dns_domains, dns_zonefiles, mail_domains, web_domains, domains_with_a_records)
+		for domain in domains_to_check)
+	ret = pool.starmap(run_domain_checks_on_domain, args, chunksize=1)
+	ret = dict(ret) # (domain, output) => { domain: output }
+	for domain in sort_domains(ret, env):
+		ret[domain].playback(output)
+
+def run_domain_checks_on_domain(domain, rounded_time, env, dns_domains, dns_zonefiles, mail_domains, web_domains, domains_with_a_records):
+	output = BufferedOutput()
+
+	# we'd move this up, but this returns non-pickleable values
+	ssl_certificates = get_ssl_certificates(env)
+
+	# The domain is IDNA-encoded in the database, but for display use Unicode.
+	try:
+		domain_display = idna.decode(domain.encode('ascii'))
+		output.add_heading(domain_display)
+	except (ValueError, UnicodeError, idna.IDNAError) as e:
+		# Looks like we have some invalid data in our database.
+		output.add_heading(domain)
+		output.print_error("Domain name is invalid: " + str(e))
+
+	if domain == env["PRIMARY_HOSTNAME"]:
+		check_primary_hostname_dns(domain, env, output, dns_domains, dns_zonefiles)
+
+	if domain in dns_domains:
+		check_dns_zone(domain, env, output, dns_zonefiles)
+
+	if domain in mail_domains:
+		check_mail_domain(domain, env, output)
+
+	if domain in web_domains:
+		check_web_domain(domain, rounded_time, ssl_certificates, env, output)
+
+	if domain in dns_domains:
+		check_dns_zone_suggestions(domain, env, output, dns_zonefiles, domains_with_a_records)
+
+	return (domain, output)
+
+def check_primary_hostname_dns(domain, env, output, dns_domains, dns_zonefiles):
+	# If a DS record is set on the zone containing this domain, check DNSSEC now.
+	has_dnssec = False
+	for zone in dns_domains:
+		if zone == domain or domain.endswith("." + zone):
+			if query_dns(zone, "DS", nxdomain=None) is not None:
+				has_dnssec = True
+				check_dnssec(zone, env, output, dns_zonefiles, is_checking_primary=True)
+
+	ip = query_dns(domain, "A")
+	ns_ips = query_dns("ns1." + domain, "A") + '/' + query_dns("ns2." + domain, "A")
+	my_ips = env['PUBLIC_IP'] + ((" / "+env['PUBLIC_IPV6']) if env.get("PUBLIC_IPV6") else "")
+
+	# Check that the ns1/ns2 hostnames resolve to A records. This information probably
+	# comes from the TLD since the information is set at the registrar as glue records.
+	# We're probably not actually checking that here but instead checking that we, as
+	# the nameserver, are reporting the right info --- but if the glue is incorrect this
+	# will probably fail.
+	if ns_ips == env['PUBLIC_IP'] + '/' + env['PUBLIC_IP']:
+		output.print_ok("Nameserver glue records are correct at registrar. [ns1/ns2.%s ↦ %s]" % (env['PRIMARY_HOSTNAME'], env['PUBLIC_IP']))
+
+	elif ip == env['PUBLIC_IP']:
+		# The NS records are not what we expect, but the domain resolves correctly, so
+		# the user may have set up external DNS. List this discrepancy as a warning.
+		output.print_warning("""Nameserver glue records (ns1.%s and ns2.%s) should be configured at your domain name
+			registrar as having the IP address of this box (%s). They currently report addresses of %s. If you have set up External DNS, this may be OK."""
+			% (env['PRIMARY_HOSTNAME'], env['PRIMARY_HOSTNAME'], env['PUBLIC_IP'], ns_ips))
+
+	else:
+		output.print_error("""Nameserver glue records are incorrect. The ns1.%s and ns2.%s nameservers must be configured at your domain name
+			registrar as having the IP address %s. They currently report addresses of %s. It may take several hours for
+			public DNS to update after a change."""
+			% (env['PRIMARY_HOSTNAME'], env['PRIMARY_HOSTNAME'], env['PUBLIC_IP'], ns_ips))
+
+	# Check that PRIMARY_HOSTNAME resolves to PUBLIC_IP[V6] in public DNS.
+	ipv6 = query_dns(domain, "AAAA") if env.get("PUBLIC_IPV6") else None
+	if ip == env['PUBLIC_IP'] and ipv6 in (None, env['PUBLIC_IPV6']):
+		output.print_ok("Domain resolves to box's IP address. [%s ↦ %s]" % (env['PRIMARY_HOSTNAME'], my_ips))
+	else:
+		output.print_error("""This domain must resolve to your box's IP address (%s) in public DNS but it currently resolves
+			to %s. It may take several hours for public DNS to update after a change. This problem may result from other
+			issues listed above."""
+			% (my_ips, ip + ((" / " + ipv6) if ipv6 is not None else "")))
+
+
+	# Check reverse DNS matches the PRIMARY_HOSTNAME. Note that it might not be
+	# a DNS zone if it is a subdomain of another domain we have a zone for.
+	existing_rdns_v4 = query_dns(dns.reversename.from_address(env['PUBLIC_IP']), "PTR")
+	existing_rdns_v6 = query_dns(dns.reversename.from_address(env['PUBLIC_IPV6']), "PTR") if env.get("PUBLIC_IPV6") else None
+	if existing_rdns_v4 == domain and existing_rdns_v6 in (None, domain):
+		output.print_ok("Reverse DNS is set correctly at ISP. [%s ↦ %s]" % (my_ips, env['PRIMARY_HOSTNAME']))
+	elif existing_rdns_v4 == existing_rdns_v6 or existing_rdns_v6 is None:
+		output.print_error("""Your box's reverse DNS is currently %s, but it should be %s. Your ISP or cloud provider will have instructions
+			on setting up reverse DNS for your box.""" % (existing_rdns_v4, domain) )
+	else:
+		output.print_error("""Your box's reverse DNS is currently %s (IPv4) and %s (IPv6), but it should be %s. Your ISP or cloud provider will have instructions
+			on setting up reverse DNS for your box.""" % (existing_rdns_v4, existing_rdns_v6, domain) )
+
+	# Check the TLSA record.
+	tlsa_qname = "_25._tcp." + domain
+	tlsa25 = query_dns(tlsa_qname, "TLSA", nxdomain=None)
+	tlsa25_expected = build_tlsa_record(env)
+	if tlsa25 == tlsa25_expected:
+		output.print_ok("""The DANE TLSA record for incoming mail is correct (%s).""" % tlsa_qname,)
+	elif tlsa25 is None:
+		if has_dnssec:
+			# Omit a warning about it not being set if DNSSEC isn't enabled,
+			# since TLSA shouldn't be used without DNSSEC.
+			output.print_warning("""The DANE TLSA record for incoming mail is not set. This is optional.""")
+	else:
+		output.print_error("""The DANE TLSA record for incoming mail (%s) is not correct. It is '%s' but it should be '%s'.
+			It may take several hours for public DNS to update after a change."""
+						% (tlsa_qname, tlsa25, tlsa25_expected))
+
+	# Check that the hostmaster@ email address exists.
+	check_alias_exists("Hostmaster contact address", "hostmaster@" + domain, env, output)
+
+def check_alias_exists(alias_name, alias, env, output):
+	mail_aliases = dict([(address, receivers) for address, receivers, *_ in get_mail_aliases(env)])
+	if alias in mail_aliases:
+		if mail_aliases[alias]:
+			output.print_ok("%s exists as a mail alias. [%s ↦ %s]" % (alias_name, alias, mail_aliases[alias]))
+		else:
+			output.print_error("""You must set the destination of the mail alias for %s to direct email to you or another administrator.""" % alias)
+	else:
+		output.print_error("""You must add a mail alias for %s which directs email to you or another administrator.""" % alias)
+
+def check_dns_zone(domain, env, output, dns_zonefiles):
+	# If a DS record is set at the registrar, check DNSSEC first because it will affect the NS query.
+	# If it is not set, we suggest it last.
+	if query_dns(domain, "DS", nxdomain=None) is not None:
+		check_dnssec(domain, env, output, dns_zonefiles)
+
+	# We provide a DNS zone for the domain. It should have NS records set up
+	# at the domain name's registrar pointing to this box. The secondary DNS
+	# server may be customized.
+	# (I'm not sure whether this necessarily tests the TLD's configuration,
+	# as it should, or if one successful NS line at the TLD will result in
+	# this query being answered by the box, which would mean the test is only
+	# half working.)
+
+	custom_dns_records = list(get_custom_dns_config(env)) # generator => list so we can reuse it
+	correct_ip = "; ".join(sorted(get_custom_dns_records(custom_dns_records, domain, "A"))) or env['PUBLIC_IP']
+	custom_secondary_ns = get_secondary_dns(custom_dns_records, mode="NS")
+	secondary_ns = custom_secondary_ns or ["ns2." + env['PRIMARY_HOSTNAME']]
+
+	existing_ns = query_dns(domain, "NS")
+	correct_ns = "; ".join(sorted(["ns1." + env['PRIMARY_HOSTNAME']] + secondary_ns))
+	ip = query_dns(domain, "A")
+
+	probably_external_dns = False
+
+	if existing_ns.lower() == correct_ns.lower():
+		output.print_ok("Nameservers are set correctly at registrar. [%s]" % correct_ns)
+	elif ip == correct_ip:
+		# The domain resolves correctly, so maybe the user is using External DNS.
+		output.print_warning("""The nameservers set on this domain at your domain name registrar should be %s. They are currently %s.
+			If you are using External DNS, this may be OK."""
+				% (correct_ns, existing_ns) )
+		probably_external_dns = True
+	else:
+		output.print_error("""The nameservers set on this domain are incorrect. They are currently %s. Use your domain name registrar's
+			control panel to set the nameservers to %s."""
+				% (existing_ns, correct_ns) )
+
+	# Check that each custom secondary nameserver resolves the IP address.
+
+	if custom_secondary_ns and not probably_external_dns:
+		for ns in custom_secondary_ns:
+			# We must first resolve the nameserver to an IP address so we can query it.
+			ns_ip = query_dns(ns, "A")
+			if not ns_ip:
+				output.print_error("Secondary nameserver %s is not valid (it doesn't resolve to an IP address)." % ns)
+				continue
+
+			# Now query it to see what it says about this domain.
+			ip = query_dns(domain, "A", at=ns_ip, nxdomain=None)
+			if ip == correct_ip:
+				output.print_ok("Secondary nameserver %s resolved the domain correctly." % ns)
+			elif ip is None:
+				output.print_error("Secondary nameserver %s is not configured to resolve this domain." % ns)
+			else:
+				output.print_error("Secondary nameserver %s is not configured correctly. (It resolved this domain as %s. It should be %s.)" % (ns, ip, correct_ip))
+
+def check_dns_zone_suggestions(domain, env, output, dns_zonefiles, domains_with_a_records):
+	# Warn if a custom DNS record is preventing this or the automatic www redirect from
+	# being served.
+	if domain in domains_with_a_records:
+		output.print_warning("""Web has been disabled for this domain because you have set a custom DNS record.""")
+	if "www." + domain in domains_with_a_records:
+		output.print_warning("""A redirect from 'www.%s' has been disabled for this domain because you have set a custom DNS record on the www subdomain.""" % domain)
+
+	# Since DNSSEC is optional, if a DS record is NOT set at the registrar suggest it.
+	# (If it was set, we did the check earlier.)
+	if query_dns(domain, "DS", nxdomain=None) is None:
+		check_dnssec(domain, env, output, dns_zonefiles)
+
+
+def check_dnssec(domain, env, output, dns_zonefiles, is_checking_primary=False):
+	# See if the domain has a DS record set at the registrar. The DS record may have
+	# several forms. We have to be prepared to check for any valid record. We've
+	# pre-generated all of the valid digests --- read them in.
+	ds_file = '/etc/nsd/zones/' + dns_zonefiles[domain] + '.ds'
+	if not os.path.exists(ds_file): return # Domain is in our database but DNS has not yet been updated.
+	ds_correct = open(ds_file).read().strip().split("\n")
+	digests = { }
+	for rr_ds in ds_correct:
+		ds_keytag, ds_alg, ds_digalg, ds_digest = rr_ds.split("\t")[4].split(" ")
+		digests[ds_digalg] = ds_digest
+
+	# Some registrars may want the public key so they can compute the digest. The DS
+	# record that we suggest using is for the KSK (and that's how the DS records were generated).
+	alg_name_map = { '7': 'RSASHA1-NSEC3-SHA1', '8': 'RSASHA256' }
+	dnssec_keys = load_env_vars_from_file(os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/%s.conf' % alg_name_map[ds_alg]))
+	dnsssec_pubkey = open(os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/' + dnssec_keys['KSK'] + '.key')).read().split("\t")[3].split(" ")[3]
+
+	# Query public DNS for the DS record at the registrar.
+	ds = query_dns(domain, "DS", nxdomain=None)
+	ds_looks_valid = ds and len(ds.split(" ")) == 4
+	if ds_looks_valid: ds = ds.split(" ")
+	if ds_looks_valid and ds[0] == ds_keytag and ds[1] == ds_alg and ds[3] == digests.get(ds[2]):
+		if is_checking_primary: return
+		output.print_ok("DNSSEC 'DS' record is set correctly at registrar.")
+	else:
+		if ds == None:
+			if is_checking_primary: return
+			output.print_warning("""This domain's DNSSEC DS record is not set. The DS record is optional. The DS record activates DNSSEC.
+				To set a DS record, you must follow the instructions provided by your domain name registrar and provide to them this information:""")
+		else:
+			if is_checking_primary:
+				output.print_error("""The DNSSEC 'DS' record for %s is incorrect. See further details below.""" % domain)
+				return
+			output.print_error("""This domain's DNSSEC DS record is incorrect. The chain of trust is broken between the public DNS system
+				and this machine's DNS server. It may take several hours for public DNS to update after a change. If you did not recently
+				make a change, you must resolve this immediately by following the instructions provided by your domain name registrar and
+				provide to them this information:""")
+		output.print_line("")
+		output.print_line("Key Tag: " + ds_keytag + ("" if not ds_looks_valid or ds[0] == ds_keytag else " (Got '%s')" % ds[0]))
+		output.print_line("Key Flags: KSK")
+		output.print_line(
+			  ("Algorithm: %s / %s" % (ds_alg, alg_name_map[ds_alg]))
+			+ ("" if not ds_looks_valid or ds[1] == ds_alg else " (Got '%s')" % ds[1]))
+			# see http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml
+		output.print_line("Digest Type: 2 / SHA-256")
+			# http://www.ietf.org/assignments/ds-rr-types/ds-rr-types.xml
+		output.print_line("Digest: " + digests['2'])
+		if ds_looks_valid and ds[3] != digests.get(ds[2]):
+			output.print_line("(Got digest type %s and digest %s which do not match.)" % (ds[2], ds[3]))
+		output.print_line("Public Key: ")
+		output.print_line(dnsssec_pubkey, monospace=True)
+		output.print_line("")
+		output.print_line("Bulk/Record Format:")
+		output.print_line("" + ds_correct[0])
+		output.print_line("")
+
+def check_mail_domain(domain, env, output):
+	# Check the MX record.
+
+	recommended_mx = "10 " + env['PRIMARY_HOSTNAME']
+	mx = query_dns(domain, "MX", nxdomain=None)
+
+	if mx is None:
+		mxhost = None
+	else:
+		# query_dns returns a semicolon-delimited list
+		# of priority-host pairs.
+		mxhost = mx.split('; ')[0].split(' ')[1]
+
+	if mxhost == None:
+		# A missing MX record is okay on the primary hostname because
+		# the primary hostname's A record (the MX fallback) is... itself,
+		# which is what we want the MX to be.
+		if domain == env['PRIMARY_HOSTNAME']:
+			output.print_ok("Domain's email is directed to this domain. [%s has no MX record, which is ok]" % (domain,))
+
+		# And a missing MX record is okay on other domains if the A record
+		# matches the A record of the PRIMARY_HOSTNAME. Actually this will
+		# probably confuse DANE TLSA, but we'll let that slide for now.
+		else:
+			domain_a = query_dns(domain, "A", nxdomain=None)
+			primary_a = query_dns(env['PRIMARY_HOSTNAME'], "A", nxdomain=None)
+			if domain_a != None and domain_a == primary_a:
+				output.print_ok("Domain's email is directed to this domain. [%s has no MX record but its A record is OK]" % (domain,))
+			else:
+				output.print_error("""This domain's DNS MX record is not set. It should be '%s'. Mail will not
+					be delivered to this box. It may take several hours for public DNS to update after a
+					change. This problem may result from other issues listed here.""" % (recommended_mx,))
+
+	elif mxhost == env['PRIMARY_HOSTNAME']:
+		good_news = "Domain's email is directed to this domain. [%s ↦ %s]" % (domain, mx)
+		if mx != recommended_mx:
+			good_news += "  This configuration is non-standard.  The recommended configuration is '%s'." % (recommended_mx,)
+		output.print_ok(good_news)
+	else:
+		output.print_error("""This domain's DNS MX record is incorrect. It is currently set to '%s' but should be '%s'. Mail will not
+			be delivered to this box. It may take several hours for public DNS to update after a change. This problem may result from
+			other issues listed here.""" % (mx, recommended_mx))
+
+	# Check that the postmaster@ email address exists. Not required if the domain has a
+	# catch-all address or domain alias.
+	if "@" + domain not in [address for address, *_ in get_mail_aliases(env)]:
+		check_alias_exists("Postmaster contact address", "postmaster@" + domain, env, output)
+
+	# Stop if the domain is listed in the Spamhaus Domain Block List.
+	# The user might have chosen a domain that was previously in use by a spammer
+	# and will not be able to reliably send mail.
+	dbl = query_dns(domain+'.dbl.spamhaus.org', "A", nxdomain=None)
+	if dbl is None:
+		output.print_ok("Domain is not blacklisted by dbl.spamhaus.org.")
+	else:
+		output.print_error("""This domain is listed in the Spamhaus Domain Block List (code %s),
+			which may prevent recipients from receiving your mail.
+			See http://www.spamhaus.org/dbl/ and http://www.spamhaus.org/query/domain/%s.""" % (dbl, domain))
+
+def check_web_domain(domain, rounded_time, ssl_certificates, env, output):
+	# See if the domain's A record resolves to our PUBLIC_IP. This is already checked
+	# for PRIMARY_HOSTNAME, for which it is required for mail specifically. For it and
+	# other domains, it is required to access its website.
+	if domain != env['PRIMARY_HOSTNAME']:
+		ok_values = []
+		for (rtype, expected) in (("A", env['PUBLIC_IP']), ("AAAA", env.get('PUBLIC_IPV6'))):
+			if not expected: continue # IPv6 is not configured
+			value = query_dns(domain, rtype)
+			if value == expected:
+				ok_values.append(value)
+			else:
+				output.print_error("""This domain should resolve to your box's IP address (%s %s) if you would like the box to serve
+					webmail or a website on this domain. The domain currently resolves to %s in public DNS. It may take several hours for
+					public DNS to update after a change. This problem may result from other issues listed here.""" % (rtype, expected, value))
+				return
+
+		# If both A and AAAA are correct...
+		output.print_ok("Domain resolves to this box's IP address. [%s ↦ %s]" % (domain, '; '.join(ok_values)))
+
+
+	# We need a TLS certificate for PRIMARY_HOSTNAME because that's where the
+	# user will log in with IMAP or webmail. Any other domain we serve a
+	# website for also needs a signed certificate.
+	check_ssl_cert(domain, rounded_time, ssl_certificates, env, output)
+
+def query_dns(qname, rtype, nxdomain='[Not Set]', at=None):
+	# Make the qname absolute by appending a period. Without this, dns.resolver.query
+	# will fall back a failed lookup to a second query with this machine's hostname
+	# appended. This has been causing some false-positive Spamhaus reports. The
+	# reverse DNS lookup will pass a dns.name.Name instance which is already
+	# absolute so we should not modify that.
+	if isinstance(qname, str):
+		qname += "."
+
+	# Use the default nameservers (as defined by the system, which is our locally
+	# running bind server), or if the 'at' argument is specified, use that host
+	# as the nameserver.
+	resolver = dns.resolver.get_default_resolver()
+	if at:
+		resolver = dns.resolver.Resolver()
+		resolver.nameservers = [at]
+
+	# Set a timeout so that a non-responsive server doesn't hold us back.
+	resolver.timeout = 5
+
+	# Do the query.
+	try:
+		response = resolver.query(qname, rtype)
+	except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
+		# Host did not have an answer for this query; not sure what the
+		# difference is between the two exceptions.
+		return nxdomain
+	except dns.exception.Timeout:
+		return "[timeout]"
+
+	# There may be multiple answers; concatenate the response. Remove trailing
+	# periods from responses since that's how qnames are encoded in DNS but is
+	# confusing for us. The order of the answers doesn't matter, so sort so we
+	# can compare to a well known order.
+
+	# Unfortunately, the response.__str__ returns bytes
+	# instead of string, if it resulted from an AAAA-query.
+	# We need to convert manually, until this is fixed:
+	# https://github.com/rthalley/dnspython/issues/204
+	#
+	# BEGIN HOTFIX
+	response_new = []
+	for r in response:
+		s = r.to_text()
+		if isinstance(s, bytes):
+			 s = s.decode('utf-8')
+		s = str(ipaddress.ip_address(s))
+		response_new.append(s)
+	response = response_new
+	# END HOTFIX
+
+	return "; ".join(sorted(str(r).rstrip('.') for r in response))
+
+def check_ssl_cert(domain, rounded_time, ssl_certificates, env, output):
+	# Check that TLS certificate is signed.
+
+	# Skip the check if the A record is not pointed here.
+	if query_dns(domain, "A", None) not in (env['PUBLIC_IP'], None): return
+
+	# Where is the certificate file stored?
+	tls_cert = get_domain_ssl_files(domain, ssl_certificates, env, allow_missing_cert=True)
+	if tls_cert is None:
+		output.print_warning("""No TLS (SSL) certificate is installed for this domain. Visitors to a website on
+			this domain will get a security warning. If you are not serving a website on this domain, you do
+			not need to take any action. Use the TLS Certificates page in the control panel to install a
+			TLS certificate.""")
+		return
+
+	# Check that the certificate is good.
+
+	cert_status, cert_status_details = check_certificate(domain, tls_cert["certificate"], tls_cert["private-key"], rounded_time=rounded_time)
+
+	if cert_status == "OK":
+		# The certificate is ok. The details has expiry info.
+		output.print_ok("TLS (SSL) certificate is signed & valid. " + cert_status_details)
+
+	elif cert_status == "SELF-SIGNED":
+		# Offer instructions for purchasing a signed certificate.
+		if domain == env['PRIMARY_HOSTNAME']:
+			output.print_error("""The TLS (SSL) certificate for this domain is currently self-signed. You will get a security
+			warning when you check or send email and when visiting this domain in a web browser (for webmail or
+			static site hosting).""")
+		else:
+			output.print_error("""The TLS (SSL) certificate for this domain is self-signed.""")
+
+	else:
+		output.print_error("The TLS (SSL) certificate has a problem: " + cert_status)
+		if cert_status_details:
+			output.print_line("")
+			output.print_line(cert_status_details)
+			output.print_line("")
+
+_apt_updates = None
+def list_apt_updates(apt_update=True):
+	# See if we have this information cached recently.
+	# Keep the information for 8 hours.
+	global _apt_updates
+	if _apt_updates is not None and _apt_updates[0] > datetime.datetime.now() - datetime.timedelta(hours=8):
+		return _apt_updates[1]
+
+	# Run apt-get update to refresh package list. This should be running daily
+	# anyway, so on the status checks page don't do this because it is slow.
+	if apt_update:
+		shell("check_call", ["/usr/bin/apt-get", "-qq", "update"])
+
+	# Run apt-get upgrade in simulate mode to get a list of what
+	# it would do.
+	simulated_install = shell("check_output", ["/usr/bin/apt-get", "-qq", "-s", "upgrade"])
+	pkgs = []
+	for line in simulated_install.split('\n'):
+		if line.strip() == "":
+			continue
+		if re.match(r'^Conf .*', line):
+			 # remove these lines, not informative
+			continue
+		m = re.match(r'^Inst (.*) \[(.*)\] \((\S*)', line)
+		if m:
+			pkgs.append({ "package": m.group(1), "version": m.group(3), "current_version": m.group(2) })
+		else:
+			pkgs.append({ "package": "[" + line + "]", "version": "", "current_version": "" })
+
+	# Cache for future requests.
+	_apt_updates = (datetime.datetime.now(), pkgs)
+
+	return pkgs
+
+def what_version_is_this(env):
+	# This function runs `git describe --abbrev=0` on the Mail-in-a-Box installation directory.
+	# Git may not be installed and Mail-in-a-Box may not have been cloned from github,
+	# so this function may raise all sorts of exceptions.
+	miab_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+	tag = shell("check_output", ["/usr/bin/git", "describe", "--abbrev=0"], env={"GIT_DIR": os.path.join(miab_dir, '.git')}).strip()
+	return tag
+
+def get_latest_miab_version():
+	# This pings https://mailinabox.email/setup.sh and extracts the tag named in
+	# the script to determine the current product version.
+	import urllib.request
+	return re.search(b'TAG=(.*)', urllib.request.urlopen("https://mailinabox.email/setup.sh?ping=1").read()).group(1).decode("utf8")
+
+def check_miab_version(env, output):
+	config = load_settings(env)
+
+	if config.get("privacy", True):
+		output.print_warning("Mail-in-a-Box version check disabled by privacy setting.")
+	else:
+		try:
+			this_ver = what_version_is_this(env)
+		except:
+			this_ver = "Unknown"
+
+		latest_ver = get_latest_miab_version()
+
+		if this_ver == latest_ver:
+			output.print_ok("Mail-in-a-Box is up to date. You are running version %s." % this_ver)
+		else:
+			output.print_error("A new version of Mail-in-a-Box is available. You are running version %s. The latest version is %s. For upgrade instructions, see https://mailinabox.email. "
+				% (this_ver, latest_ver))
+
+def run_and_output_changes(env, pool):
+	import json
+	from difflib import SequenceMatcher
+
+	out = ConsoleOutput()
+
+	# Run status checks.
+	cur = BufferedOutput()
+	run_checks(True, env, cur, pool)
+
+	# Load previously saved status checks.
+	cache_fn = "/var/cache/mailinabox/status_checks.json"
+	if os.path.exists(cache_fn):
+		prev = json.load(open(cache_fn))
+
+		# Group the serial output into categories by the headings.
+		def group_by_heading(lines):
+			from collections import OrderedDict
+			ret = OrderedDict()
+			k = []
+			ret["No Category"] = k
+			for line_type, line_args, line_kwargs in lines:
+				if line_type == "add_heading":
+					k = []
+					ret[line_args[0]] = k
+				else:
+					k.append((line_type, line_args, line_kwargs))
+			return ret
+		prev_status = group_by_heading(prev)
+		cur_status = group_by_heading(cur.buf)
+
+		# Compare the previous to the current status checks
+		# category by category.
+		for category, cur_lines in cur_status.items():
+			if category not in prev_status:
+				out.add_heading(category + " -- Added")
+				BufferedOutput(with_lines=cur_lines).playback(out)
+			else:
+				# Actual comparison starts here...
+				prev_lines = prev_status[category]
+				def stringify(lines):
+					return [json.dumps(line) for line in lines]
+				diff = SequenceMatcher(None, stringify(prev_lines), stringify(cur_lines)).get_opcodes()
+				for op, i1, i2, j1, j2 in diff:
+					if op == "replace":
+						out.add_heading(category + " -- Previously:")
+					elif op == "delete":
+						out.add_heading(category + " -- Removed")
+					if op in ("replace", "delete"):
+						BufferedOutput(with_lines=prev_lines[i1:i2]).playback(out)
+
+					if op == "replace":
+						out.add_heading(category + " -- Currently:")
+					elif op == "insert":
+						out.add_heading(category + " -- Added")
+					if op in ("replace", "insert"):
+						BufferedOutput(with_lines=cur_lines[j1:j2]).playback(out)
+
+		for category, prev_lines in prev_status.items():
+			if category not in cur_status:
+				out.add_heading(category)
+				out.print_warning("This section was removed.")
+
+	# Store the current status checks output for next time.
+	os.makedirs(os.path.dirname(cache_fn), exist_ok=True)
+	with open(cache_fn, "w") as f:
+		json.dump(cur.buf, f, indent=True)
+
+class FileOutput:
+	def __init__(self, buf, width):
+		self.buf = buf
+		self.width = width
+
+	def add_heading(self, heading):
+		print(file=self.buf)
+		print(heading, file=self.buf)
+		print("=" * len(heading), file=self.buf)
+
+	def print_ok(self, message):
+		self.print_block(message, first_line="✓  ")
+
+	def print_error(self, message):
+		self.print_block(message, first_line="✖  ")
+
+	def print_warning(self, message):
+		self.print_block(message, first_line="?  ")
+
+	def print_block(self, message, first_line="   "):
+		print(first_line, end='', file=self.buf)
+		message = re.sub("\n\s*", " ", message)
+		words = re.split("(\s+)", message)
+		linelen = 0
+		for w in words:
+			if self.width and (linelen + len(w) > self.width-1-len(first_line)):
+				print(file=self.buf)
+				print("   ", end="", file=self.buf)
+				linelen = 0
+			if linelen == 0 and w.strip() == "": continue
+			print(w, end="", file=self.buf)
+			linelen += len(w)
+		print(file=self.buf)
+
+	def print_line(self, message, monospace=False):
+		for line in message.split("\n"):
+			self.print_block(line)
+
+class ConsoleOutput(FileOutput):
+	def __init__(self):
+		self.buf = sys.stdout
+
+		# Do nice line-wrapping according to the size of the terminal.
+		# The 'stty' program queries standard input for terminal information.
+		if sys.stdin.isatty():
+			try:
+				self.width = int(shell('check_output', ['stty', 'size']).split()[1])
+			except:
+				self.width = 76
+
+		else:
+			# However if standard input is not a terminal, we would get
+			# "stty: standard input: Inappropriate ioctl for device". So
+			# we test with sys.stdin.isatty first, and if it is not a
+			# terminal don't do any line wrapping. When this script is
+			# run from cron, or if stdin has been redirected, this happens.
+			self.width = None
+
+class BufferedOutput:
+	# Record all of the instance method calls so we can play them back later.
+	def __init__(self, with_lines=None):
+		self.buf = [] if not with_lines else with_lines
+	def __getattr__(self, attr):
+		if attr not in ("add_heading", "print_ok", "print_error", "print_warning", "print_block", "print_line"):
+			raise AttributeError
+		# Return a function that just records the call & arguments to our buffer.
+		def w(*args, **kwargs):
+			self.buf.append((attr, args, kwargs))
+		return w
+	def playback(self, output):
+		for attr, args, kwargs in self.buf:
+			getattr(output, attr)(*args, **kwargs)
+
+
+if __name__ == "__main__":
+	from utils import load_environment
+
+	env = load_environment()
+	pool = multiprocessing.pool.Pool(processes=10)
+
+	if len(sys.argv) == 1:
+		run_checks(False, env, ConsoleOutput(), pool)
+
+	elif sys.argv[1] == "--show-changes":
+		run_and_output_changes(env, pool)
+
+	elif sys.argv[1] == "--check-primary-hostname":
+		# See if the primary hostname appears resolvable and has a signed certificate.
+		domain = env['PRIMARY_HOSTNAME']
+		if query_dns(domain, "A") != env['PUBLIC_IP']:
+			sys.exit(1)
+		ssl_certificates = get_ssl_certificates(env)
+		tls_cert = get_domain_ssl_files(domain, ssl_certificates, env)
+		if not os.path.exists(tls_cert["certificate"]):
+			sys.exit(1)
+		cert_status, cert_status_details = check_certificate(domain, tls_cert["certificate"], tls_cert["private-key"], warn_if_expiring_soon=False)
+		if cert_status != "OK":
+			sys.exit(1)
+		sys.exit(0)
+
+	elif sys.argv[1] == "--version":
+		print(what_version_is_this(env))