aboutsummaryrefslogtreecommitdiffstats
path: root/util/prosodyctl/check.lua
blob: 09d787ec46b6d0bf9f1fa0519af0b05be1569484 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
local configmanager = require "core.configmanager";
local show_usage = require "util.prosodyctl".show_usage;
local show_warning = require "util.prosodyctl".show_warning;
local is_prosody_running = require "util.prosodyctl".isrunning;
local dependencies = require "util.dependencies";
local socket = require "socket";
local socket_url = require "socket.url";
local jid_split = require "util.jid".prepped_split;
local modulemanager = require "core.modulemanager";
local async = require "util.async";
local httputil = require "util.http";

local function check_ojn(check_type, target_host)
	local http = require "net.http"; -- .new({});
	local json = require "util.json";

	local response, err = async.wait_for(http.request(
		("https://observe.jabber.network/api/v1/check/%s"):format(httputil.urlencode(check_type)),
		{
			method="POST",
			headers={["Accept"] = "application/json"; ["Content-Type"] = "application/json"},
			body=json.encode({target=target_host}),
		}));

	if not response then
		return false, err;
	end

	if response.code ~= 200 then
		return false, ("API replied with non-200 code: %d"):format(response.code);
	end

	local decoded_body, err = json.decode(response.body);
	if decoded_body == nil then
		return false, ("Failed to parse API JSON: %s"):format(err)
	end

	local success = decoded_body["success"];
	return success == true, nil;
end

local function check_probe(base_url, probe_module, target)
	local http = require "net.http"; -- .new({});
	local params = httputil.formencode({ module = probe_module; target = target })
	local response, err = async.wait_for(http.request(base_url .. "?" .. params));

	if not response then return false, err; end

	if response.code ~= 200 then return false, ("API replied with non-200 code: %d"):format(response.code); end

	for line in response.body:gmatch("[^\r\n]+") do
		local probe_success = line:match("^probe_success%s+(%d+)");

		if probe_success == "1" then
			return true;
		elseif probe_success == "0" then
			return false;
		end
	end
	return false, "Probe endpoint did not return a success status";
end

local function skip_bare_jid_hosts(host)
	if jid_split(host) then
		-- See issue #779
		return false;
	end
	return true;
end

local function check(arg)
	if arg[1] == "--help" then
		show_usage([[check]], [[Perform basic checks on your Prosody installation]]);
		return 1;
	end
	local what = table.remove(arg, 1);
	local array = require "util.array";
	local set = require "util.set";
	local it = require "util.iterators";
	local ok = true;
	local function disabled_hosts(host, conf) return host ~= "*" and conf.enabled ~= false; end
	local function enabled_hosts() return it.filter(disabled_hosts, pairs(configmanager.getconfig())); end
	if not (what == nil or what == "disabled" or what == "config" or what == "dns" or what == "certs" or what == "connectivity") then
		show_warning("Don't know how to check '%s'. Try one of 'config', 'dns', 'certs', 'disabled' or 'connectivity'.", what);
		show_warning("Note: The connectivity check will connect to a remote server.");
		return 1;
	end
	if not what or what == "disabled" then
		local disabled_hosts_set = set.new();
		for host, host_options in it.filter("*", pairs(configmanager.getconfig())) do
			if host_options.enabled == false then
				disabled_hosts_set:add(host);
			end
		end
		if not disabled_hosts_set:empty() then
			local msg = "Checks will be skipped for these disabled hosts: %s";
			if what then msg = "These hosts are disabled: %s"; end
			show_warning(msg, tostring(disabled_hosts_set));
			if what then return 0; end
			print""
		end
	end
	if not what or what == "config" then
		print("Checking config...");
		local obsolete = set.new({ --> remove
			"archive_cleanup_interval",
			"cross_domain_bosh",
			"cross_domain_websocket",
			"dns_timeout",
			"muc_log_cleanup_interval",
			"s2s_dns_resolvers",
			"setgid",
			"setuid",
		});
		local function instead_use(kind, name, value)
			if kind == "option" then
				if value then
					return string.format("instead, use '%s = %q'", name, value);
				else
					return string.format("instead, use '%s'", name);
				end
			elseif kind == "module" then
				return string.format("instead, add %q to '%s'", name, value or "modules_enabled");
			elseif kind == "community" then
				return string.format("instead, add %q from %s", name, value or "prosody-modules");
			end
			return kind
		end
		local deprecated_replacements = {
			anonymous_login = instead_use("option", "authentication", "anonymous");
			daemonize = "instead, use the --daemonize/-D or --foreground/-F command line flags";
			disallow_s2s = instead_use("module", "s2s");
			no_daemonize = "instead, use the --daemonize/-D or --foreground/-F command line flags";
			require_encryption = "instead, use 'c2s_require_encryption' and 's2s_require_encryption'";
			vcard_compatibility = instead_use("community", "mod_compat_vcard");
			use_libevent = instead_use("option", "network_backend", "event");
			whitelist_registration_only = instead_use("option", "allowlist_registration_only");
			registration_whitelist = instead_use("option", "registration_allowlist");
			registration_blacklist = instead_use("option", "registration_blocklist");
			blacklist_on_registration_throttle_overload = instead_use("blocklist_on_registration_throttle_overload");
		};
		-- FIXME all the singular _port and _interface options are supposed to be deprecated too
		local deprecated_ports = { bosh = "http", legacy_ssl = "c2s_direct_tls" };
		local port_suffixes = set.new({ "port", "ports", "interface", "interfaces", "ssl" });
		for port, replacement in pairs(deprecated_ports) do
			for suffix in port_suffixes do
				local rsuffix = (suffix == "port" or suffix == "interface") and suffix.."s" or suffix;
				deprecated_replacements[port.."_"..suffix] = "instead, use '"..replacement.."_"..rsuffix.."'"
			end
		end
		local deprecated = set.new(array.collect(it.keys(deprecated_replacements)));
		local known_global_options = set.new({
			"access_control_allow_credentials",
			"access_control_allow_headers",
			"access_control_allow_methods",
			"access_control_max_age",
			"admin_socket",
			"body_size_limit",
			"bosh_max_inactivity",
			"bosh_max_polling",
			"bosh_max_wait",
			"buffer_size_limit",
			"c2s_close_timeout",
			"c2s_stanza_size_limit",
			"c2s_tcp_keepalives",
			"c2s_timeout",
			"component_stanza_size_limit",
			"component_tcp_keepalives",
			"consider_bosh_secure",
			"consider_websocket_secure",
			"console_banner",
			"console_prettyprint_settings",
			"daemonize",
			"gc",
			"http_default_host",
			"http_errors_always_show",
			"http_errors_default_message",
			"http_errors_detailed",
			"http_errors_messages",
			"http_max_buffer_size",
			"http_max_content_size",
			"installer_plugin_path",
			"limits",
			"limits_resolution",
			"log",
			"multiplex_buffer_size",
			"network_backend",
			"network_default_read_size",
			"network_settings",
			"openmetrics_allow_cidr",
			"openmetrics_allow_ips",
			"pidfile",
			"plugin_paths",
			"plugin_server",
			"prosodyctl_timeout",
			"prosody_group",
			"prosody_user",
			"run_as_root",
			"s2s_close_timeout",
			"s2s_insecure_domains",
			"s2s_require_encryption",
			"s2s_secure_auth",
			"s2s_secure_domains",
			"s2s_stanza_size_limit",
			"s2s_tcp_keepalives",
			"s2s_timeout",
			"statistics",
			"statistics_config",
			"statistics_interval",
			"tcp_keepalives",
			"tls_profile",
			"trusted_proxies",
			"umask",
			"use_dane",
			"use_ipv4",
			"use_ipv6",
			"websocket_frame_buffer_limit",
			"websocket_frame_fragment_limit",
			"websocket_get_response_body",
			"websocket_get_response_text",
		});
		local config = configmanager.getconfig();
		-- Check that we have any global options (caused by putting a host at the top)
		if it.count(it.filter("log", pairs(config["*"]))) == 0 then
			ok = false;
			print("");
			print("    No global options defined. Perhaps you have put a host definition at the top")
			print("    of the config file? They should be at the bottom, see https://prosody.im/doc/configure#overview");
		end
		if it.count(enabled_hosts()) == 0 then
			ok = false;
			print("");
			if it.count(it.filter("*", pairs(config))) == 0 then
				print("    No hosts are defined, please add at least one VirtualHost section")
			elseif config["*"]["enabled"] == false then
				print("    No hosts are enabled. Remove enabled = false from the global section or put enabled = true under at least one VirtualHost section")
			else
				print("    All hosts are disabled. Remove enabled = false from at least one VirtualHost section")
			end
		end
		if not config["*"].modules_enabled then
			print("    No global modules_enabled is set?");
			local suggested_global_modules;
			for host, options in enabled_hosts() do --luacheck: ignore 213/host
				if not options.component_module and options.modules_enabled then
					suggested_global_modules = set.intersection(suggested_global_modules or set.new(options.modules_enabled), set.new(options.modules_enabled));
				end
			end
			if suggested_global_modules and not suggested_global_modules:empty() then
				print("    Consider moving these modules into modules_enabled in the global section:")
				print("    "..tostring(suggested_global_modules / function (x) return ("%q"):format(x) end));
			end
			print();
		end

		do -- Check for modules enabled both normally and as components
			local modules = set.new(config["*"]["modules_enabled"]);
			for host, options in enabled_hosts() do
				local component_module = options.component_module;
				if component_module and modules:contains(component_module) then
					print(("    mod_%s is enabled both in modules_enabled and as Component %q %q"):format(component_module, host, component_module));
					print("    This means the service is enabled on all VirtualHosts as well as the Component.");
					print("    Are you sure this what you want? It may cause unexpected behaviour.");
				end
			end
		end

		-- Check for global options under hosts
		local global_options = set.new(it.to_array(it.keys(config["*"])));
		local obsolete_global_options = set.intersection(global_options, obsolete);
		if not obsolete_global_options:empty() then
			print("");
			print("    You have some obsolete options you can remove from the global section:");
			print("    "..tostring(obsolete_global_options))
			ok = false;
		end
		local deprecated_global_options = set.intersection(global_options, deprecated);
		if not deprecated_global_options:empty() then
			print("");
			print("    You have some deprecated options in the global section:");
			for option in deprecated_global_options do
				print(("    '%s' -- %s"):format(option, deprecated_replacements[option]));
			end
			ok = false;
		end
		for host, options in it.filter(function (h) return h ~= "*" end, pairs(configmanager.getconfig())) do
			local host_options = set.new(it.to_array(it.keys(options)));
			local misplaced_options = set.intersection(host_options, known_global_options);
			for name in pairs(options) do
				if name:match("^interfaces?")
				or name:match("_ports?$") or name:match("_interfaces?$")
				or (name:match("_ssl$") and not name:match("^[cs]2s_ssl$")) then
					misplaced_options:add(name);
				end
			end
			-- FIXME These _could_ be misplaced, but we would have to check where the corresponding module is loaded to be sure
			misplaced_options:exclude(set.new({ "external_service_port", "turn_external_port" }));
			if not misplaced_options:empty() then
				ok = false;
				print("");
				local n = it.count(misplaced_options);
				print("    You have "..n.." option"..(n>1 and "s " or " ").."set under "..host.." that should be");
				print("    in the global section of the config file, above any VirtualHost or Component definitions,")
				print("    see https://prosody.im/doc/configure#overview for more information.")
				print("");
				print("    You need to move the following option"..(n>1 and "s" or "")..": "..table.concat(it.to_array(misplaced_options), ", "));
			end
		end
		for host, options in enabled_hosts() do
			local host_options = set.new(it.to_array(it.keys(options)));
			local subdomain = host:match("^[^.]+");
			if not(host_options:contains("component_module")) and (subdomain == "jabber" or subdomain == "xmpp"
			   or subdomain == "chat" or subdomain == "im") then
				print("");
				print("    Suggestion: If "..host.. " is a new host with no real users yet, consider renaming it now to");
				print("     "..host:gsub("^[^.]+%.", "")..". You can use SRV records to redirect XMPP clients and servers to "..host..".");
				print("     For more information see: https://prosody.im/doc/dns");
			end
		end
		local all_modules = set.new(config["*"].modules_enabled);
		local all_options = set.new(it.to_array(it.keys(config["*"])));
		for host in enabled_hosts() do
			all_options:include(set.new(it.to_array(it.keys(config[host]))));
			all_modules:include(set.new(config[host].modules_enabled));
		end
		for mod in all_modules do
			if mod:match("^mod_") then
				print("");
				print("    Modules in modules_enabled should not have the 'mod_' prefix included.");
				print("    Change '"..mod.."' to '"..mod:match("^mod_(.*)").."'.");
			elseif mod:match("^auth_") then
				print("");
				print("    Authentication modules should not be added to modules_enabled,");
				print("    but be specified in the 'authentication' option.");
				print("    Remove '"..mod.."' from modules_enabled and instead add");
				print("        authentication = '"..mod:match("^auth_(.*)").."'");
				print("    For more information see https://prosody.im/doc/authentication");
			elseif mod:match("^storage_") then
				print("");
				print("    storage modules should not be added to modules_enabled,");
				print("    but be specified in the 'storage' option.");
				print("    Remove '"..mod.."' from modules_enabled and instead add");
				print("        storage = '"..mod:match("^storage_(.*)").."'");
				print("    For more information see https://prosody.im/doc/storage");
			end
		end
		if all_modules:contains("vcard") and all_modules:contains("vcard_legacy") then
			print("");
			print("    Both mod_vcard_legacy and mod_vcard are enabled but they conflict");
			print("    with each other. Remove one.");
		end
		if all_modules:contains("pep") and all_modules:contains("pep_simple") then
			print("");
			print("    Both mod_pep_simple and mod_pep are enabled but they conflict");
			print("    with each other. Remove one.");
		end
		for host, host_config in pairs(config) do --luacheck: ignore 213/host
			if type(rawget(host_config, "storage")) == "string" and rawget(host_config, "default_storage") then
				print("");
				print("    The 'default_storage' option is not needed if 'storage' is set to a string.");
				break;
			end
		end
		local require_encryption = set.intersection(all_options, set.new({
			"require_encryption", "c2s_require_encryption", "s2s_require_encryption"
		})):empty();
		local ssl = dependencies.softreq"ssl";
		if not ssl then
			if not require_encryption then
				print("");
				print("    You require encryption but LuaSec is not available.");
				print("    Connections will fail.");
				ok = false;
			end
		elseif not ssl.loadcertificate then
			if all_options:contains("s2s_secure_auth") then
				print("");
				print("    You have set s2s_secure_auth but your version of LuaSec does ");
				print("    not support certificate validation, so all s2s connections will");
				print("    fail.");
				ok = false;
			elseif all_options:contains("s2s_secure_domains") then
				local secure_domains = set.new();
				for host in enabled_hosts() do
					if config[host].s2s_secure_auth == true then
						secure_domains:add("*");
					else
						secure_domains:include(set.new(config[host].s2s_secure_domains));
					end
				end
				if not secure_domains:empty() then
					print("");
					print("    You have set s2s_secure_domains but your version of LuaSec does ");
					print("    not support certificate validation, so s2s connections to/from ");
					print("    these domains will fail.");
					ok = false;
				end
			end
		elseif require_encryption and not all_modules:contains("tls") then
			print("");
			print("    You require encryption but mod_tls is not enabled.");
			print("    Connections will fail.");
			ok = false;
		end

		do
			local global_modules = set.new(config["*"].modules_enabled);
			local registration_enabled_hosts = {};
			for host in enabled_hosts() do
				local host_modules = set.new(config[host].modules_enabled) + global_modules;
				local allow_registration = config[host].allow_registration;
				local mod_register = host_modules:contains("register");
				local mod_register_ibr = host_modules:contains("register_ibr");
				local mod_invites_register = host_modules:contains("invites_register");
				local registration_invite_only = config[host].registration_invite_only;
				local is_vhost = not config[host].component_module;
				if is_vhost and (mod_register_ibr or (mod_register and allow_registration))
				   and not (mod_invites_register and registration_invite_only) then
					table.insert(registration_enabled_hosts, host);
				end
			end
			if #registration_enabled_hosts > 0 then
				table.sort(registration_enabled_hosts);
				print("");
				print("    Public registration is enabled on:");
				print("        "..table.concat(registration_enabled_hosts, ", "));
				print("");
				print("        If this is intentional, review our guidelines on running a public server");
				print("        at https://prosody.im/doc/public_servers - otherwise, consider switching to");
				print("        invite-based registration, which is more secure.");
			end
		end

		print("Done.\n");
	end
	if not what or what == "dns" then
		local dns = require "net.dns";
		pcall(function ()
			local unbound = require"net.unbound";
			local unbound_config = configmanager.get("*", "unbound") or {};
			unbound_config.hoststxt = false; -- don't look at /etc/hosts
			configmanager.set("*", "unbound", unbound_config);
			unbound.dns.purge(); -- ensure the above config is used
			dns = unbound.dns;
		end)
		local idna = require "util.encodings".idna;
		local ip = require "util.ip";
		local c2s_ports = set.new(configmanager.get("*", "c2s_ports") or {5222});
		local s2s_ports = set.new(configmanager.get("*", "s2s_ports") or {5269});
		local c2s_tls_ports = set.new(configmanager.get("*", "c2s_direct_tls_ports") or {});
		local s2s_tls_ports = set.new(configmanager.get("*", "s2s_direct_tls_ports") or {});

		if set.new(configmanager.get("*", "modules_enabled")):contains("net_multiplex") then
			local multiplex_ports = set.new(configmanager.get("*", "ports") or {});
			local multiplex_tls_ports = set.new(configmanager.get("*", "ssl_ports") or {});
			if not multiplex_ports:empty() then
				c2s_ports = c2s_ports + multiplex_ports;
				s2s_ports = s2s_ports + multiplex_ports;
			end
			if not multiplex_tls_ports:empty() then
				c2s_tls_ports = c2s_tls_ports + multiplex_tls_ports;
				s2s_tls_ports = s2s_tls_ports + multiplex_tls_ports;
			end
		end

		local c2s_srv_required, s2s_srv_required, c2s_tls_srv_required, s2s_tls_srv_required;
		if not c2s_ports:contains(5222) then
			c2s_srv_required = true;
		end
		if not s2s_ports:contains(5269) then
			s2s_srv_required = true;
		end
		if not c2s_tls_ports:empty() then
			c2s_tls_srv_required = true;
		end
		if not s2s_tls_ports:empty() then
			s2s_tls_srv_required = true;
		end

		local problem_hosts = set.new();

		local external_addresses, internal_addresses = set.new(), set.new();

		local fqdn = socket.dns.tohostname(socket.dns.gethostname());
		if fqdn then
			do
				local res = dns.lookup(idna.to_ascii(fqdn), "A");
				if res then
					for _, record in ipairs(res) do
						external_addresses:add(record.a);
					end
				end
			end
			do
				local res = dns.lookup(idna.to_ascii(fqdn), "AAAA");
				if res then
					for _, record in ipairs(res) do
						external_addresses:add(record.aaaa);
					end
				end
			end
		end

		local local_addresses = require"util.net".local_addresses() or {};

		for addr in it.values(local_addresses) do
			if not ip.new_ip(addr).private then
				external_addresses:add(addr);
			else
				internal_addresses:add(addr);
			end
		end

		if external_addresses:empty() then
			print("");
			print("   Failed to determine the external addresses of this server. Checks may be inaccurate.");
			c2s_srv_required, s2s_srv_required = true, true;
		end

		local v6_supported = not not socket.tcp6;
		local use_ipv4 = configmanager.get("*", "use_ipv4") ~= false;
		local use_ipv6 = v6_supported and configmanager.get("*", "use_ipv6") ~= false;

		local function trim_dns_name(n)
			return (n:gsub("%.$", ""));
		end

		for jid, host_options in enabled_hosts() do
			local all_targets_ok, some_targets_ok = true, false;
			local node, host = jid_split(jid);

			local modules, component_module = modulemanager.get_modules_for_host(host);
			if component_module then
				modules:add(component_module);
			end

			local is_component = not not host_options.component_module;
			print("Checking DNS for "..(is_component and "component" or "host").." "..jid.."...");
			if node then
				print("Only the domain part ("..host..") is used in DNS.")
			end
			local target_hosts = set.new();
			if modules:contains("c2s") then
				local res = dns.lookup("_xmpp-client._tcp."..idna.to_ascii(host)..".", "SRV");
				if res and #res > 0 then
					for _, record in ipairs(res) do
						if record.srv.target == "." then -- TODO is this an error if mod_c2s is enabled?
							print("    'xmpp-client' service disabled by pointing to '.'"); -- FIXME Explain better what this is
							break;
						end
						local target = trim_dns_name(record.srv.target);
						target_hosts:add(target);
						if not c2s_ports:contains(record.srv.port) then
							print("    SRV target "..target.." contains unknown client port: "..record.srv.port);
						end
					end
				else
					if c2s_srv_required then
						print("    No _xmpp-client SRV record found for "..host..", but it looks like you need one.");
						all_targets_ok = false;
					else
						target_hosts:add(host);
					end
				end
			end
			if modules:contains("c2s") and c2s_tls_srv_required then
				local res = dns.lookup("_xmpps-client._tcp."..idna.to_ascii(host)..".", "SRV");
				if res and #res > 0 then
					for _, record in ipairs(res) do
						if record.srv.target == "." then -- TODO is this an error if mod_c2s is enabled?
							print("    'xmpps-client' service disabled by pointing to '.'"); -- FIXME Explain better what this is
							break;
						end
						local target = trim_dns_name(record.srv.target);
						target_hosts:add(target);
						if not c2s_tls_ports:contains(record.srv.port) then
							print("    SRV target "..target.." contains unknown Direct TLS client port: "..record.srv.port);
						end
					end
				else
					print("    No _xmpps-client SRV record found for "..host..", but it looks like you need one.");
					all_targets_ok = false;
				end
			end
			if modules:contains("s2s") then
				local res = dns.lookup("_xmpp-server._tcp."..idna.to_ascii(host)..".", "SRV");
				if res and #res > 0 then
					for _, record in ipairs(res) do
						if record.srv.target == "." then -- TODO Is this an error if mod_s2s is enabled?
							print("    'xmpp-server' service disabled by pointing to '.'"); -- FIXME Explain better what this is
							break;
						end
						local target = trim_dns_name(record.srv.target);
						target_hosts:add(target);
						if not s2s_ports:contains(record.srv.port) then
							print("    SRV target "..target.." contains unknown server port: "..record.srv.port);
						end
					end
				else
					if s2s_srv_required then
						print("    No _xmpp-server SRV record found for "..host..", but it looks like you need one.");
						all_targets_ok = false;
					else
						target_hosts:add(host);
					end
				end
			end
			if modules:contains("s2s") and s2s_tls_srv_required then
				local res = dns.lookup("_xmpps-server._tcp."..idna.to_ascii(host)..".", "SRV");
				if res and #res > 0 then
					for _, record in ipairs(res) do
						if record.srv.target == "." then -- TODO is this an error if mod_s2s is enabled?
							print("    'xmpps-server' service disabled by pointing to '.'"); -- FIXME Explain better what this is
							break;
						end
						local target = trim_dns_name(record.srv.target);
						target_hosts:add(target);
						if not s2s_tls_ports:contains(record.srv.port) then
							print("    SRV target "..target.." contains unknown Direct TLS server port: "..record.srv.port);
						end
					end
				else
					print("    No _xmpps-server SRV record found for "..host..", but it looks like you need one.");
					all_targets_ok = false;
				end
			end
			if target_hosts:empty() then
				target_hosts:add(host);
			end

			if target_hosts:contains("localhost") then
				print("    Target 'localhost' cannot be accessed from other servers");
				target_hosts:remove("localhost");
			end

			local function check_address(target)
				local A, AAAA = dns.lookup(idna.to_ascii(target), "A"), dns.lookup(idna.to_ascii(target), "AAAA");
				local prob = {};
				if use_ipv4 and not (A and #A > 0) then table.insert(prob, "A"); end
				if use_ipv6 and not (AAAA and #AAAA > 0) then table.insert(prob, "AAAA"); end
				return prob;
			end

			if modules:contains("proxy65") then
				local proxy65_target = configmanager.get(host, "proxy65_address") or host;
				if type(proxy65_target) == "string" then
					local prob = check_address(proxy65_target);
					if #prob > 0 then
						print("    File transfer proxy "..proxy65_target.." has no "..table.concat(prob, "/")
						.." record. Create one or set 'proxy65_address' to the correct host/IP.");
					end
				else
					print("    proxy65_address for "..host.." should be set to a string, unable to perform DNS check");
				end
			end

			local known_http_modules = set.new { "bosh"; "http_files"; "http_file_share"; "http_openmetrics"; "websocket" };
			local function contains_match(hayset, needle)
				for member in hayset do if member:find(needle) then return true end end
			end

			if modules:contains("http") or not set.intersection(modules, known_http_modules):empty()
				or contains_match(modules, "^http_") or contains_match(modules, "_web$") then

				local http_host = configmanager.get(host, "http_host") or host;
				local http_internal_host = http_host;
				local http_url = configmanager.get(host, "http_external_url");
				if http_url then
					local url_parse = require "socket.url".parse;
					local external_url_parts = url_parse(http_url);
					if external_url_parts then
						http_host = external_url_parts.host;
					else
						print("    The 'http_external_url' setting is not a valid URL");
					end
				end

				local prob = check_address(http_host);
				if #prob > 1 then
					print("    HTTP service " .. http_host .. " has no " .. table.concat(prob, "/") .. " record. Create one or change "
									.. (http_url and "'http_external_url'" or "'http_host'").." to the correct host.");
				end

				if http_host ~= http_internal_host then
					print("    Ensure the reverse proxy sets the HTTP Host header to '" .. http_internal_host .. "'");
				end
			end

			if not use_ipv4 and not use_ipv6 then
				print("    Both IPv6 and IPv4 are disabled, Prosody will not listen on any ports");
				print("    nor be able to connect to any remote servers.");
				all_targets_ok = false;
			end

			for target_host in target_hosts do
				local host_ok_v4, host_ok_v6;
				do
					local res = dns.lookup(idna.to_ascii(target_host), "A");
					if res then
						for _, record in ipairs(res) do
							if external_addresses:contains(record.a) then
								some_targets_ok = true;
								host_ok_v4 = true;
							elseif internal_addresses:contains(record.a) then
								host_ok_v4 = true;
								some_targets_ok = true;
								print("    "..target_host.." A record points to internal address, external connections might fail");
							else
								print("    "..target_host.." A record points to unknown address "..record.a);
								all_targets_ok = false;
							end
						end
					end
				end
				do
					local res = dns.lookup(idna.to_ascii(target_host), "AAAA");
					if res then
						for _, record in ipairs(res) do
							if external_addresses:contains(record.aaaa) then
								some_targets_ok = true;
								host_ok_v6 = true;
							elseif internal_addresses:contains(record.aaaa) then
								host_ok_v6 = true;
								some_targets_ok = true;
								print("    "..target_host.." AAAA record points to internal address, external connections might fail");
							else
								print("    "..target_host.." AAAA record points to unknown address "..record.aaaa);
								all_targets_ok = false;
							end
						end
					end
				end

				if host_ok_v4 and not use_ipv4 then
					print("    Host "..target_host.." does seem to resolve to this server but IPv4 has been disabled");
					all_targets_ok = false;
				end

				if host_ok_v6 and not use_ipv6 then
					print("    Host "..target_host.." does seem to resolve to this server but IPv6 has been disabled");
					all_targets_ok = false;
				end

				local bad_protos = {}
				if use_ipv4 and not host_ok_v4 then
					table.insert(bad_protos, "IPv4");
				end
				if use_ipv6 and not host_ok_v6 then
					table.insert(bad_protos, "IPv6");
				end
				if #bad_protos > 0 then
					print("    Host "..target_host.." does not seem to resolve to this server ("..table.concat(bad_protos, "/")..")");
				end
				if host_ok_v6 and not v6_supported then
					print("    Host "..target_host.." has AAAA records, but your version of LuaSocket does not support IPv6.");
					print("      Please see https://prosody.im/doc/ipv6 for more information.");
				elseif host_ok_v6 and not use_ipv6 then
					print("    Host "..target_host.." has AAAA records, but IPv6 is disabled.");
					-- TODO Tell them to drop the AAAA records or enable IPv6?
					print("      Please see https://prosody.im/doc/ipv6 for more information.");
				end
			end
			if not all_targets_ok then
				print("    "..(some_targets_ok and "Only some" or "No").." targets for "..host.." appear to resolve to this server.");
				if is_component then
					print("    DNS records are necessary if you want users on other servers to access this component.");
				end
				problem_hosts:add(host);
			end
			print("");
		end
		if not problem_hosts:empty() then
			print("");
			print("For more information about DNS configuration please see https://prosody.im/doc/dns");
			print("");
			ok = false;
		end
	end
	if not what or what == "certs" then
		local cert_ok;
		print"Checking certificates..."
		local x509_verify_identity = require"util.x509".verify_identity;
		local create_context = require "core.certmanager".create_context;
		local ssl = dependencies.softreq"ssl";
		-- local datetime_parse = require"util.datetime".parse_x509;
		local load_cert = ssl and ssl.loadcertificate;
		-- or ssl.cert_from_pem
		if not ssl then
			print("LuaSec not available, can't perform certificate checks")
			if what == "certs" then cert_ok = false end
		elseif not load_cert then
			print("This version of LuaSec (" .. ssl._VERSION .. ") does not support certificate checking");
			cert_ok = false
		else
			for host in it.filter(skip_bare_jid_hosts, enabled_hosts()) do
				print("Checking certificate for "..host);
				-- First, let's find out what certificate this host uses.
				local host_ssl_config = configmanager.rawget(host, "ssl")
					or configmanager.rawget(host:match("%.(.*)"), "ssl");
				local global_ssl_config = configmanager.rawget("*", "ssl");
				local ok, err, ssl_config = create_context(host, "server", host_ssl_config, global_ssl_config);
				if not ok then
					print("  Error: "..err);
					cert_ok = false
				elseif not ssl_config.certificate then
					print("  No 'certificate' found for "..host)
					cert_ok = false
				elseif not ssl_config.key then
					print("  No 'key' found for "..host)
					cert_ok = false
				else
					local key, err = io.open(ssl_config.key); -- Permissions check only
					if not key then
						print("    Could not open "..ssl_config.key..": "..err);
						cert_ok = false
					else
						key:close();
					end
					local cert_fh, err = io.open(ssl_config.certificate); -- Load the file.
					if not cert_fh then
						print("    Could not open "..ssl_config.certificate..": "..err);
						cert_ok = false
					else
						print("  Certificate: "..ssl_config.certificate)
						local cert = load_cert(cert_fh:read"*a"); cert_fh:close();
						if not cert:validat(os.time()) then
							print("    Certificate has expired.")
							cert_ok = false
						elseif not cert:validat(os.time() + 86400) then
							print("    Certificate expires within one day.")
							cert_ok = false
						elseif not cert:validat(os.time() + 86400*7) then
							print("    Certificate expires within one week.")
						elseif not cert:validat(os.time() + 86400*31) then
							print("    Certificate expires within one month.")
						end
						if configmanager.get(host, "component_module") == nil
							and not x509_verify_identity(host, "_xmpp-client", cert) then
							print("    Not valid for client connections to "..host..".")
							cert_ok = false
						end
						if (not (configmanager.get(host, "anonymous_login")
							or configmanager.get(host, "authentication") == "anonymous"))
							and not x509_verify_identity(host, "_xmpp-server", cert) then
							print("    Not valid for server-to-server connections to "..host..".")
							cert_ok = false
						end
					end
				end
			end
		end
		if cert_ok == false then
			print("")
			print("For more information about certificates please see https://prosody.im/doc/certificates");
			ok = false
		end
		print("")
	end
	-- intentionally not doing this by default
	if what == "connectivity" then
		local _, prosody_is_running = is_prosody_running();
		if configmanager.get("*", "pidfile") and not prosody_is_running then
			print("Prosody does not appear to be running, which is required for this test.");
			print("Start it and then try again.");
			return 1;
		end

		local checker = "observe.jabber.network";
		local probe_instance;
		local probe_modules = {
			["xmpp-client"] = "c2s_normal_auth";
			["xmpp-server"] = "s2s_normal";
			["xmpps-client"] = nil; -- TODO
			["xmpps-server"] = nil; -- TODO
		};
		local probe_settings = configmanager.get("*", "connectivity_probe");
		if type(probe_settings) == "string" then
			probe_instance = probe_settings;
		elseif type(probe_settings) == "table" and type(probe_settings.url) == "string" then
			probe_instance = probe_settings.url;
			if type(probe_settings.modules) == "table" then
				probe_modules = probe_settings.modules;
			end
		elseif probe_settings ~= nil then
			print("The 'connectivity_probe' setting not understood.");
			print("Expected an URL or a table with 'url' and 'modules' fields");
			print("See https://prosody.im/doc/prosodyctl#check for more information."); -- FIXME
			return 1;
		end

		local check_api;
		if probe_instance then
			local parsed_url = socket_url.parse(probe_instance);
			if not parsed_url then
				print(("'connectivity_probe' is not a valid URL: %q"):format(probe_instance));
				print("Set it to the URL of an XMPP Blackbox Exporter instance and try again");
				return 1;
			end
			checker = parsed_url.host;

			function check_api(protocol, host)
				local target = socket_url.build({scheme="xmpp",path=host});
				local probe_module = probe_modules[protocol];
				if not probe_module then
					return nil, "Checking protocol '"..protocol.."' is currently unsupported";
				end
				return check_probe(probe_instance, probe_module, target);
			end
		else
			check_api = check_ojn;
		end

		for host in it.filter(skip_bare_jid_hosts, enabled_hosts()) do
			local modules, component_module = modulemanager.get_modules_for_host(host);
			if component_module then
				modules:add(component_module)
			end

			print("Checking external connectivity for "..host.." via "..checker)
			local function check_connectivity(protocol)
				local success, err = check_api(protocol, host);
				if not success and err ~= nil then
					print(("  %s: Failed to request check at API: %s"):format(protocol, err))
				elseif success then
					print(("  %s: Works"):format(protocol))
				else
					print(("  %s: Check service failed to establish (secure) connection"):format(protocol))
					ok = false
				end
			end

			if modules:contains("c2s") then
				check_connectivity("xmpp-client")
				if configmanager.get("*", "c2s_direct_tls_ports") then
					check_connectivity("xmpps-client");
				end
			end

			if modules:contains("s2s") then
				check_connectivity("xmpp-server")
				if configmanager.get("*", "s2s_direct_tls_ports") then
					check_connectivity("xmpps-server");
				end
			end

			print()
		end
		print("Note: The connectivity check only checks the reachability of the domain.")
		print("Note: It does not ensure that the check actually reaches this specific prosody instance.")
	end
	if not ok then
		print("Problems found, see above.");
	else
		print("All checks passed, congratulations!");
	end
	return ok and 0 or 2;
end

return {
	check = check;
};