Everything You Need to Know About DNS in 5 Minutes

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EVERYTHING YOU NEED TO KNOW ABOUT DNS IN 5 MINUTES ANTHONY EDEN Monday, September 26, 11 DNS is the Domain Name System

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WHY DO YOU CARE? Monday, September 26, 11 DNS seems scary to most people But it is one of the core technologies that makes the Internet work If you care about your personal brand or corporate brand you will have a domain name and need DNS It’s no fun to be ignorant

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A BRIEF HISTORY Monday, September 26, 11 November 1987 by Dr. Paul Mockapetris That’s 24 years old Some of you probably weren’t born yet (I feel old now)

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A BIT ABOUT DOMAIN NAMES Monday, September 26, 11 top-level domains are com, net, org typically you may purchase a second level (example.com) or third level (example.co.uk) you are a registrant. you buy a domain from a registrar. the master list of domains is managed by a registry.

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DNS, HOW DOES IT WORK? Monday, September 26, 11 Two types of servers: authoritative and recursive. Your computer asks a nearby recursing server to ﬁnd a name. That recursor tries to ﬁnd it locally, but if not it

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A RECORDS Monday, September 26, 11 Technical description: an A record maps a name to an IP address An IP address is used to route packets on a network to a machine

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Name TTL (time to live) Type Content Monday, September 26, 11

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CNAME RECORDS Monday, September 26, 11 An alias from one name to another

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MX RECORDS Monday, September 26, 11 Tells mail delivery agents what servers to deliver your mail to.

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Name TTL (time to live) Type Content Monday, September 26, 11

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SOA Records Monday, September 26, 11 Start of authority Sent by an authoritative server to indicate that it is the authority for a domain

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NS RECORDS Monday, September 26, 11 Delegate a subdomain. The registry has one or more of these for each domain you have that tells recursors where to look for the authoritative record.

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TXT RECORDS Monday, September 26, 11 Multi-purpose. Various spam reduction schemes, such as SPF and DKIM

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EVERYTHING ELSE Monday, September 26, 11 SRV for referencing VOIP and chat services NAPTR for phone numbers to SIP addresses (also for VOIP) AAAA (quad A records) for IPv6 servers PTR for mapping an IP address back to a name

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CHECK YOURSELF Monday, September 26, 11

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DIG Monday, September 26, 11

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Monday, September 26, 11

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WHOIS Monday, September 26, 11

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Monday, September 26, 11

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WHY DO YOU CARE? Monday, September 26, 11 With a little bit of knowledge You turn DNS into something that is fun And into something that can be played with