In domain configuration at CloudFlare, the DNS section stores the record definitions. What is the exact purpose of NS record here? If configured, it shows something like:  Type | Name       | Value                     | TTL -----+------------+---------------------------+---------- NS   | domain.com | managed by ns1.domain.com | Automatic   But the NS at authoritative DNS server (registrar) is configured accordingly to the CloudFlare assignments:  adi.ns.cloudflare.com bob.ns.cloudflare.com   And the latter are presented if the domain is queried for example by any DNS propagation checker (e.g. whatsmydns.net).  The domain is being managed by their DNS anyway, so what's the purpose of defining the NS records in CloudFlare configuration panel?
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$ORIGIN example.com. ; not necessary, using this to self-document  $TTL 3600 @        IN     SOA   ns1.example.com. admin.example.com. (                       1970010100 7200 1800 1209600 300)  @        IN     NS   ns1.example.com. @        IN     NS   ns2.example.com.  @        IN     A    198.51.100.1 ns1      IN     A    198.51.100.2 ns2      IN     A    198.51.100.3  sub1     IN     NS   ns1.example.edu.  sub2     IN     NS   ns1.sub2 ns1.sub2 IN     A    203.0.113.1 ; inline glue record   The role of a NS record beneath the apex of a domain is well-understood; they exist to delegate authority for a subdomain to another nameserver. Examples of this above would include the NS records for sub1 and sub2. These allow the nameserver to hand out referrals for portions of the domain that it does not consider itself authoritative for.  The purpose of the NS records at the apex of a domain, ns1 and ns2 in this case, seem to be less understood by the internet at large. My understanding (which may not be holistic) is as follows:   They are not used by caching DNS servers in order to determine the authoritative servers for the domain. This is handled by , which is defined at the registrar level. The registrar never uses this information to generate the glue records. They  used to delegate authority for the entire domain to other nameservers. Trying to do so with software such as ISC BIND will not result in the "expected" referral behavior at all, as the nameserver will continue to consider itself authoritative for the zone. They are not used by the nameserver to determine whether it should return authoritative responses (AA flag set) or not; that behavior is defined by whether the software is told to be a master or a slave for the zone. Most nameserver software will quite happily serve apex NS records that disagree with the information contained by the upstream glue records, which will in turn cause well-known DNS validation websites to generate warnings for the domain.   With this being the case, what are we left with? Why are we defining this information if it doesn't appear to be consumed by caching DNS servers on the internet at large?
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Let's Encrypt has  they have:     Turned on support for the ACME DNS challenge   How do I make ./letsencrypt-auto generate a new certificate using DNS challenge domain validation?  EDIT I mean: How do I avoid http/https port binding, by using the newly announced  feature (2015-01-20) that lets you prove the domain ownership by adding a specific TXT record in the DNS zone of the target domain?
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I am new to the world of setting up servers and am baffled by the term hostname and fully qualified domain name (FQDN). For example, if I want to set up a server that hosts files on the local network i.e. a file server, what would I use a hostname such as myfileserver or something else? What if I wanted to set up a web server, mail server, etc. that external users could access?
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This is a  about DNS Propagation   How long does it take for an the various types of records to propagate? Do some propagate faster than others?  Why does it take time for DNS records to propagate and how does it work?
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I have a website with DNS pointing to my hosting account at ns1.a.com and ns2.a.com  I want to switch a hosting account (to ns1.b.com and ns2.b.com).   However if I simply change the DNS the site will be inaccessible until the change is complete, is there anyway to change host for a website without suffering from downtime?
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When I register a new domain, I send it to my hosting provider by assigning it its domain name servers in the registar's settings. For example, with Digital Ocean, I input the following:  ns1.digitalocean.com ns2.digitalocean.com ns3.digitalocean.com   I then add the domain settings in the A record of my server. It just occurred to me that anyone else on the same hosting provider can add an A record with a domain I own.   Is there anything preventing this from occurring? if 2 different servers that use the same domain name server try to assign a domain to themselves through the A records, where would the domain actually resolve when you enter it in the browser? what prevents domain name collisions on the same DNS server?
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We have a custom java web app. We are setting it up in instances in different vps (different providers, different locations). We have for example:  Instance 1: http://server1/app1 Instance 2: http://server1/app2 Instance 3: http://server2/app3   Each instance is independent and self contained. We have several docens of this instances and will continue to add them.   My question is regarding the dns managment, as we want to map different subdomains to the instances.   client1.mypp.com  &gt; http://server1/app1 client2.mypp.com  &gt; http://server1/app2 client3.mypp.com  &gt; http://server2/app3  clientN.mypp.com  &gt; http://anyserver/appN   Right now we are adding the A records manually to the DNS records to relate subdomain to the ip. We will develop some code to do it using the API of the DNS provider.   Is this the most appropiate aproach? Should we use some kind of proxy instead? We expect to have thousands of isntances accros different servers. I am interested in perfomance and availability.
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I have a server at mysite.no-ip.org. Everything is working fine and I have a blog and owncloud that I access writing mysite.no-ip.org/blog and mysite.no-ip.org/owncloud. Now, I want to create subdomains so that I can write blog.mysite.no-ip.org and owncloud.mysite.no-ip.org.  I have looked a lot into it and the simplest tutorial was this one which I followed.   Except that I am not on my server but ssh into it remotely so if I use localhost I cannot see if this works I believe. This is my first obstacle, can I follow this tutorial without being present next to the server?  I also just discovered CNAME records which (I am not completely sure) seem necessary to what I want to do. I use no-ip.org and I have tried to follow something like this but this is not really clear either   Does anyone have any pointers? This is quite shady to me and I have no idea if I am far from the solution or really close (at least if I could try localhost that would be a first step in order to check my Apache conf but I can't even do it since I ssh).  Anyways, thanks for your help in advance. Any help, link is welcomed.
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I am trying to understand how /etc/resolv.conf /etc/nsswitch.conf exactly works and what is significance of nameserver entry 127.0.1.1  I did strace ping google.com to get to know about the system calls involved , one part is :  stat64("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=172, ...}) = 0 socket(PF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.1.1")}, 16) = 0 gettimeofday({1413780874, 913366}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0)    = 1 ([{fd=4, revents=POLLOUT}]) send(4, "\0040\1\0\0\1\0\0\0\0\0\0\6google\3com\0\0\1\0\1", 28, MSG_NOSIGNAL) = 28 poll([{fd=4, events=POLLIN}], 1, 5000)  = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [204])               = 0 recvfrom(4, "\0040\201\200\0\1\0\v\0\0\0\0\6google\3com\0\0\1\0\1\300\f\0\1"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.1.1")}, [16]) = 204 close(4)                                = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(1025), sin_addr=inet_addr("173.194.123.36")}, 16) = 0 getsockname(4, {sa_family=AF_INET, sin_port=htons(58830), sin_addr=inet_addr("192.168.1.13")}, [16]) = 0 close(4)   can any one please explain what is going on here ? specially connect on 127.0.1.1 as it is namsserver entry in my resolv.conf Why we need to make socket connection to 127.0.1.1 ? and how do we get response from it ?
80309
I have servers hosted at a hosting provider and they also host the DNS records for my domain names. Now I want to add subdomains that are resolved by my own DNS service. So for example:   the hosting provider's name server knows the IP address for econemon.com one of my servers knows the IP address for ftp.econemon.com   Also,   unknown or undefined subdomains should be routed to the same IP as the parent domain on failure of my DNS service, it would be great if the requests all go to the IP address that is associated with econemon.com, but I'm not sure how that should work.   Now, I've read through the Wikipedia articles on DNS to dust off my knowledge, but the part that leaves me confused is: how does a client know which server to ask for the IP address for ftp.econemon.com? Does it get that information from the hoster? If so, do I have to register the subdomain there (and what would I need my name server for then)?
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This is a direct follow-on to . , I'd add the "-AlwaysAppendSearchDomains" argument to the mDNSResponder plist file so that all local resolver lookups added the search domains, regardless of whether there was a period in the label to be looked up. For example, whether I try to ssh to hostname foo.bar or foo, the search domain of baz.com should be tried, not only for the latter case, as was (and is) the default behavior.   Now, it looks like the mDNSResponder is gone, replaced with discoveryd. I cannot find a similar option to get it to always appending the search domain. Suggestions? I'd rather not go the route of using a non-default local resolver, but I'd consider it as an option. For now, I'll just type in the long FQDNs, but I'd really rather not.  Thanks, Pete
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This question was originally asked here:   To summarise: "When I go to my registrar and purchase example.com , I will tell my registrar that my nameservers are ns1.example.org and ns2.example.org".  But please can somebody clarify the following:  After registration, the .com registry will now have a record that tells a resolver needs to visit ns1.example.org or ns2.example.org in order to find out the IP address of example.com. The IP address resides in an A record in a zone file on ns1.example.org and has a identical copy on ns2.example.org.  However, inside this file, there must also be 2 NS records which list ns1.example.org and ns2.example.org as the nameservers. But since we are already on one of these servers, this appears do be duplicated information.   The answer originally given to the question said the nameservers listed in the zone file are "authoritative". If the nameservers didn't match, then the authoritative nameservers would take precedence. That's all very well and good, but the resolver arrived at the nameserver using the nameservers listed in the .com registry, and if the nameserver's didn't match, then the resolver would be looking for the zone file on the wrong nameserver and wouldn't be able to find it.  Or is it a case of the .com registry extracts nameserver information from the zone file ns record? (But then I suppose if you change the ns record the zone file without telling the registry, then it would have no way of knowing where to look.)   Thanks
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I want to find out all the subdomains of a given domain. I found a hint which tells me to dig the authoritative Nameserver with the following option:  dig @ns1.foo.bar some_domain.com axfr   But this never works. Has anyone a better idea/approach
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I'm currently trying to set up a small static website with my domain from NameCheap using AWS S3, but I'm having trouble correctly pointing requests to the corresponding S3 bucket.  These are my configurations for the services I use:  NameCheap  CNAME         www  example.com.s3-website-ap-northeast-1.amazonaws.com. URL Redirect  @    http://www.example.com/   AWS S3  Static Hosting example.com.s3-website-ap-northeast-1.amazonaws.com.   I am fairly new to web hosting/domain stuff so please bear with me, but from what I understand from my registrar configuration is: users entering the naked domain example.com are redirected to www.example.com which then points to the AWS S3 bucket. Then the CNAME record then points to the corresponding AWS bucket.  Howeverwhen I try to visit www.example.com I somehow get pointed to the www.example.com bucket instead of the example.com bucket landing me to the AWS Bucket not found page.  Extra Details   I've checked with DNS Checker that www.example.com's CNAME record indeed points to example.com.s3-website-ap-northeast-1.amazonaws.com.. I've also tried making a www.example.com bucket then redirecting it to example.com but it seems it points to the actual domain instead of the bucket therefore causing a redirect loop. example.com-&gt;www.example.com-&gt;www.example.com (Bucket)-&gt;example.com-&gt;∞
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I have several machines running Debian, and during install, I left the domain name field blank. This hasn't affected anything so far, but I'm curious what the correct thing to set that field to is if you don't have a registered web domain and your IP is dynamically set ( gives a different IP every few months). Apologies if this is a newb question, but I can't find any results via Google.  What is the proper domain name for a home desktop with a dynamic IP address?
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, we  what the , and they're pretty simple.  Namely, it can be summed up in a single sentence.    For example, if I were to incorporate and register the hopelessn00b.com domain, my internal AD forest should be named internal.hopelessn00b.com or ad.hopelessn00b.com or corp.hopelessn00b.com.  There are overwhelmingly compelling reasons to avoid using  or , but I'm having a hard time finding similarly compelling reasons to avoid using the root domain (hopelessn00b.com) as my domain name and use a subdomain such as corp.hopelessn00b.com instead.  Really, the only justification I can seem to find is that accessing the external website from internal requires an  A name DNS record and typing www. in front of the website name in a browser, which is pretty "meh" as far as problems go.  So, what am I missing?  Why is it so much better to use ad.hopelessn00b.com as my Active Directory forest name over hopelessn00b.com?  Just for the record, it's really my employer that needs convincing - the boss man is back-peddling, and after giving me the go ahead to create a new AD forest named corp.hopelessn00b'semployer.com for our internal network, he's wanting to stick with an AD forest named hopelessn00b'semployer.com (the same as our externally registered domain).  I'm hoping that I can get some compelling reason or reasons that the best practice is the better option, so I can convince him of that... because it seems easier than rage quitting and/or finding a new job, at least for the moment.  Right now, "Microsoft best practices" and internally accessing the public website for our company don't seem to be cutting it, and I'm really, really, really hoping someone here has something more convincing.
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I was checking out my reverse-DNS entry of my domain the other day which is run from a dedicated server.   I noticed that another person/company had their domain pointing to my server? I have no idea who this company is or why they are pointing their domain at my server IP?  How can I go about stopping this or forcing them to change?