Public DNS Servers Flashcards
What does an internet service provider almost always give you access to as part of the service it provides?
a recursive name server
What’s usually all I need for my computer to communicate with other devices on the internet
recursive name server
what do most businesses usually run
their own DNS servers
what are needed to resolve names of internal hosts, naming computers, printers.
Your own name servers
What service provider option is becoming more and more popular?
Using DNS as a service provider
what should I have in case I experience problems with my own DNS?
backup solution
Nameservers specifically set up so anyone can use them for free. Some organizations use these. Using them can help troubleshoot any name resolution problems. some people use them for all resolution needs.
public DNS servers
What does lore say the most common Public DNS servers were run by?
Level 3 communications, one of the largest ISP in the world.
What ISP is so large that they do business selling connectivity to their network to other ISP that actually deal with consumers? they don’t even deal with end users.
Level 3 Communications
What are the IP addresses for Level 3’s Public DNS servers? available for public use for almost 20 years now, but not ever officially acknowledged or advertised.
4.2.2.1 through 4.2.2.6
What are Google’s public IPs for it’s public DNS servers? These are documented by google to be used for free by anyone
8.8.8.8 and 8.8.4.4
how are most public DNS servers available globally?
anycast
What is an easy way to redirect your users to malicious sites
Hijacking outbound DNS requests with faulty responses (inject a fake entry, resolve request to a fake site)
What should I always make sure a name sever is run by?
A reputable company, and try to use teh name servers provided by my own ISP outside of troubleshooting scenarios.
What do most DNS servers do to ICMP echo requests?
respond for testing general internet connectivity using Ping.
