prosodyctl: check dns: List discovered addresses for diagnostic purposes

It is very common to get the "unknown address" warning with this command, but
people do not always understand it, or know how to debug it. Now we clearly
show the addresses that prosodyctl discovered.

1 files changed, 16 insertions, 0 deletions

diff --git a/util/prosodyctl/check.lua b/util/prosodyctl/check.lua
index 31adee8f..70f9e7b0 100644
--- a/util/prosodyctl/check.lua
+++ b/util/prosodyctl/check.lua
@@ -560,6 +560,8 @@ local function check(arg)
 			return (n:gsub("%.$", ""));
 		end
 
+		local unknown_addresses = set.new();
+
 		for jid, host_options in enabled_hosts() do
 			local all_targets_ok, some_targets_ok = true, false;
 			local node, host = jid_split(jid);
@@ -742,6 +744,7 @@ local function check(arg)
 								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);
+								unknown_addresses:add(record.a);
 								all_targets_ok = false;
 							end
 						end
@@ -760,6 +763,7 @@ local function check(arg)
 								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);
+								unknown_addresses:add(record.aaaa);
 								all_targets_ok = false;
 							end
 						end
@@ -805,6 +809,18 @@ local function check(arg)
 			print("");
 		end
 		if not problem_hosts:empty() then
+			if not unknown_addresses:empty() then
+				print("");
+				print("Some of your DNS records point to unknown IP addresses. This may be expected if your server");
+				print("is behind a NAT or proxy. The unrecognized addresses were:");
+				print("");
+				print("    Unrecognized: "..tostring(unknown_addresses));
+				print("");
+				print("The addresses we found on this system are:");
+				print("");
+				print("    Internal: "..tostring(internal_addresses));
+				print("    External: "..tostring(external_addresses));
+			end
 			print("");
 			print("For more information about DNS configuration please see https://prosody.im/doc/dns");
 			print("");