commit - 808c291c76b7ecb4ae13b6ee12e8afe658b627c1
commit + d21afce2b6fdc919a80c4eb1d6ba781c1cf63f3c
blob - 640df4ee3e81b7def928c2e4b2e3a3256a5574c8
blob + b445958159e85bdd03cc4b6328c1c59bb0938df1
--- INSTALL
+++ INSTALL
@@ -11,6 +11,14 @@
 
 I. Upgrade Information
 ~~~~~~~~~~~~~~~~~~~~~~
+
+Differences to version 19.x
+
+- Starting with ngIRCd 20, users can "cloak" their hostname only when the
+  configuration variable "CloakHostModeX" (introduced in 19.2) is set.
+  Otherwise, only IRC opertators, other servers, and services are allowed to
+  set mode +x. This prevents regular users from changing their hostmask to
+  the name of the IRC server itself, which confused quite a few people ;-)
 
 Differences to version 17
 
blob - 7380c6eb5c70308b030097aadf58a9ab3bc933e4
blob + 90f638d811219282b34af51c8cf8369e7548e4f7
--- src/ngircd/irc-mode.c
+++ src/ngircd/irc-mode.c
@@ -278,9 +278,15 @@ Client_Mode( CLIENT *Client, REQUEST *Req, CLIENT *Ori
 				ok = IRC_WriteStrClient(Origin,
 							ERR_RESTRICTED_MSG,
 							Client_ID(Origin));
-			else
+			else if (!set || Conf_CloakHostModeX[0]
+				 || Client_Type(Client) == CLIENT_SERVER
+				 || Client_OperByMe(Client)) {
 				x[0] = 'x';
 				send_RPL_HOSTHIDDEN_MSG = true;
+			} else
+				ok = IRC_WriteStrClient(Origin,
+							ERR_NOPRIVILEGES_MSG,
+							Client_ID(Origin));
 			break;
 		default:
 			if (Client_Type(Client) != CLIENT_SERVER) {