Episode 7
Bonus: Glue records
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Wait...
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Something is missing here!
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How could the resolver find 'ns1.dnsimple.com' before 'dnsimple.com'?
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Since 'ns1.dnsimple.com' is a subdomain of 'dnsimple.com', how could we resolve 'ns1.dnsimple.com' without resolving 'dnsimple.com' first?
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Isn't the search going backwards?
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Wouldn't we get stuck in a loop at some point?
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For example, let's say that the authoritative server for domain.com is ns1.domain.com
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If I wanted to browse domain.com, the .COM TLD would tell me to get the IP address from the authoritative server: ns1.domain.comGo ask ns1.domain.com
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ns1.domain.com is a subdomain of domain.comWe cannot get to a subdomain without getting to the domain first!
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Stuck in a loop!
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So, what happened? How come the resolver was able to find 'dnsimple.com' through 'ns1.dnsimple.com'?
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Simple!Glue records!
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Glue records?
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Exactly!
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Awesome!I'll explain then!
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When the resolver asked the .COM TLD about dnsimple.com, extra information was attached to that response.
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The resolver got at least one IP address for each name server.
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We call that the glue!
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So the resolver not only got the name of the authoritative name server, it also got the IP address.
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Thus breaking the circular dependency.
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Nice! I understand it now!
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Glue records rock!
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Yes, they do!hahaha, thanks!
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You made it through the end! Now is a good time to watch the video that we made for this comic!