From the course: IT Security Foundations: Network Security
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Safeguarding DNS
From the course: IT Security Foundations: Network Security
Safeguarding DNS
- [Instructor] Domain Name System is an application layer protocol that's essential to any network. DNS resolves host names to an IP address, and it uses Port 53 over UDP or TCP. In general, DNS will use UDP because we want our responses fast. However, for a full zone transfer, TCP is used. Normal queries and responses occur when a client sends a request to a DNS server for an IP address. The server then responds with information, but it can ask other servers for the information as well. DNS failures will prevent hosts from communicating or locating each other. There are many different types of DNS records, as we see here. Let's point out a couple of examples. Here is an A record, which is a 32-bit IP version four address. A quad A is for IP version six. And an MX record is for a mail exchange server. Using DNS started back in 1983. During this time, there was no consideration for any security methods to protect DNS. As networks grew and evolved, DNS remained an insecure protocol that…
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