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I am trying to build my own DNS. I have one server which I would like to use as DNS server.

  1. Why, according to RFC2182 section 5 (https://tools.ietf.org/html/rfc2182#section-5) I must have TWO servers (3 recommended)?

I tried creating ns1.example.com and ns2.example.com pointing to same IP and it works for some TLDs fine but for my .us domain it doesn't open the website.

  1. Why some TLDs does not work with just one server (two ns pointing to same IP)?

Sorry if the quiestion is boring. Thanks!

marked as duplicate by HBruijn Oct 24 '17 at 13:31

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  • It is a recommended failsafe solution. If one NS go offline, then your domain and hsots are still online. I personally use 4 NS for all domains. – Ipor Sircer Oct 24 '17 at 13:08
  • 1) That entire RFC is for "Selection and Operation of Secondary DNS Servers", which means IF you're setting-up secondary server(s), you need to follow those recommendations. I believe you're just using one server and as such it'll be the master. So not sure why you're referring to RFC2182. 2) You need to provide more details for that. What type of DNS server you're using,configuration details, error logs etc. Don't assume that everyone on internet knows about your set-up – Nehal Dattani Oct 24 '17 at 13:08

Various problems can cause a server to be unavailable for extended periods - during such a period, a zone with only two listed servers is actually running with just one. Since any server may occasionally be unavailable, for all kinds of reasons, this zone is likely, at times, to have no functional servers at all.

You need more than one for high availability, because you could have server issues ore network issues. Depending on the availability you are looking for, more servers give better uptime probability, but sometimes worst performances.

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