diff --git a/src/ngircd/client.c b/src/ngircd/client.c
index 2466c717..f163f72c 100644
--- a/src/ngircd/client.c
+++ b/src/ngircd/client.c
@@ -905,6 +905,16 @@ Client_CheckNick(CLIENT *Client, char *Nick)
 		return false;
 	}
 
+	if (Client_Type(Client) != CLIENT_SERVER
+	    && Client_Type(Client) != CLIENT_SERVICE) {
+		/* Make sure that this isn't a restricted/forbidden nick name */
+		if (Conf_NickIsBlocked(Nick)) {
+			IRC_WriteStrClient(Client, ERR_FORBIDDENNICKNAME_MSG,
+					   Client_ID(Client), Nick);
+			return false;
+		}
+	}
+
 	/* Nickname already registered? */
 	if (Client_Search(Nick)) {
 		IRC_WriteStrClient(Client, ERR_NICKNAMEINUSE_MSG,
diff --git a/src/ngircd/conf.c b/src/ngircd/conf.c
index 16ad98c2..41b5469a 100644
--- a/src/ngircd/conf.c
+++ b/src/ngircd/conf.c
@@ -651,6 +651,27 @@ Conf_NickIsService(int ConfServer, const char *Nick)
 	return MatchCaseInsensitive(Conf_Server[ConfServer].svs_mask, Nick);
 }
 
+/**
+ * Check if the given nick name is blocked for "normal client" use.
+ *
+ * @param ConfServer The server index or NONE to check all configured servers.
+ * @param Nick The nick name to check.
+ * @returns true if the given nick name belongs to an "IRC service".
+ */
+GLOBAL bool
+Conf_NickIsBlocked(const char *Nick)
+{
+	int i;
+
+	for(i = 0; i < MAX_SERVERS; i++) {
+		if (!Conf_Server[i].name[0])
+			continue;
+		if (Conf_NickIsService(i, Nick))
+			return true;
+	}
+	return false;
+}
+
 /**
  * Initialize configuration settings with their default values.
  */
diff --git a/src/ngircd/conf.h b/src/ngircd/conf.h
index 72c80390..8e66c07c 100644
--- a/src/ngircd/conf.h
+++ b/src/ngircd/conf.h
@@ -1,6 +1,6 @@
 /*
  * ngIRCd -- The Next Generation IRC Daemon
- * Copyright (c)2001-2011 Alexander Barton (alex@barton.de) and Contributors.
+ * Copyright (c)2001-2012 Alexander Barton (alex@barton.de) and Contributors.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -245,6 +245,7 @@ GLOBAL bool Conf_DisableServer PARAMS(( const char *Name ));
 GLOBAL bool Conf_AddServer PARAMS(( const char *Name, UINT16 Port, const char *Host, const char *MyPwd, const char *PeerPwd ));
 
 GLOBAL bool Conf_NickIsService PARAMS((int ConfServer, const char *Nick));
+GLOBAL bool Conf_NickIsBlocked PARAMS((const char *Nick));
 
 /* Password required by WEBIRC command */
 GLOBAL char Conf_WebircPwd[CLIENT_PASS_LEN];
diff --git a/src/ngircd/messages.h b/src/ngircd/messages.h
index 96ff2dea..9ad6be17 100644
--- a/src/ngircd/messages.h
+++ b/src/ngircd/messages.h
@@ -112,6 +112,7 @@
 #define ERR_NONICKNAMEGIVEN_MSG		"431 %s :No nickname given"
 #define ERR_ERRONEUSNICKNAME_MSG	"432 %s %s :Erroneous nickname"
 #define ERR_NICKNAMETOOLONG_MSG		"432 %s %s :Nickname too long, max. %u characters"
+#define ERR_FORBIDDENNICKNAME_MSG	"432 %s %s :Nickname is forbidden/blocked"
 #define ERR_NICKNAMEINUSE_MSG		"433 %s %s :Nickname already in use"
 #define ERR_USERNOTINCHANNEL_MSG	"441 %s %s %s :They aren't on that channel"
 #define ERR_NOTONCHANNEL_MSG		"442 %s %s :You are not on that channel"