Update 'Bind9 DNS Server'

Bind9-DNS-Server.md

@@ -110,6 +110,21 @@ primary IN      A       192.168.0.40
 60      IN      PTR     mail.linuxtechi.local.
 ```
 
+**Extra**: example of working forward configuration:
+```
+$TTL    604800
+@       IN      SOA     novinmedrd.ir.  mehranmd19.gmail.com. (
+                              2         ; Serial
+                         604800         ; Refresh
+                          86400         ; Retry
+                        2419200         ; Expire
+                         604800 )       ; Negative Cache TTL
+;
+@       IN      NS      localhost.
+@       IN      A       45.139.102.166
+www     IN      A       45.139.102.166
+```
+
 Save file & exit. Now all we have to do is to restart the BIND service to implement the changes made.
 
 ```