Use spkifp instead of sslclientcertfp in example conf.

Add example link block for services (but reject if user does not
change the default password)

doc/conf/examples/example.conf

@@ -215,16 +215,33 @@ link hub.mynet.org
 		options { ssl; };
 	};
 
-	password "00:11:22:33:44:55:66:77:88:99:AA:BB:CC:DD:EE:FF"; /* SSL fingerprint of other server */
+	/* We use the SPKI fingerprint of the other server for authentication.
+	 * Run './unrealircd spkifp' on the other side to get it.
+	 * NOTE: requires UnrealIRCd 4.0.16 or later.
+	 */
+	password "AABBCCDDEEFFGGHHIIJJKKLLMMNNOOPPQQRRSSTTUUV=" { spkifp; };
+
+	class servers;
+};
+
+/* The link block for services is usually much simpler.
+ * For more information about what Services are,
+ * see https://www.unrealircd.org/docs/Services
+ */
+link services.mynet.org
+{
+	incoming {
+		mask 127.0.0.1;
+	};
+
+	password "changemeplease";
 
 	class servers;
 };
 
 /* U-lines give other servers (even) more power/commands.
  * If you use services you must add them here.
- * NEVER put the name of a (normal) UnrealIRCd server here!!!
- * ( If you wonder what Services are then see
- *   https://www.unrealircd.org/docs/Services )
+ * NEVER put the name of an UnrealIRCd server here!!!
  */
 ulines {
 	services.mynet.org;

src/auth.c

@@ -507,6 +507,12 @@ int	Auth_Check(aClient *cptr, anAuthStruct *as, char *para)
 		case AUTHTYPE_PLAINTEXT:
 			if (!para)
 				return -1;
+			if (!strcmp(as->data, "changemeplease") && !strcmp(para, as->data))
+			{
+				sendto_realops("Rejecting default password 'changemeplease'. "
+				               "Please change the password in the configuration file.");
+				return -1;
+			}
 			/* plain text compare */
 			if (!strcmp(para, as->data))
 				return 2;