Another important topic that will show up on both the CCENT Exam and the CCNA Exam is DNS. This post will cover a basic DNS configuration on your Cisco Router.
Your router will need to connect to an external dns server either from your ISP or a public dns server so that you can have internet access. A DNS server will translate a domain name like facebook.com to an ip address like 188.8.131.52. These translations will be cached in your Cisco router. So that when another computer inside of your local network needs to translate facebook.com again it will not have to query the external server, but just use what is in the cache.