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Questions tagged [domain-name-system]

The Domain Name System, usually referred to by the acronym DNS, is a hierarchical, distributed database where the keys are domain names. Questions involving publicly accessible domains should include the real, Fully Qualified Domain Name (FQDN)

DNS is the Domain Name System, a hierarchical, distributed database where the keys are domain names.

The primary references are:

  • RFC 1034 - Domain Names - Concepts and Facilities
  • RFC 1035 - Domain Names - Implementation and Specification

These documents collectively form STD 13. RFC 2181 is a frequently cited reference for STD 13 that addresses some of the more confusing areas of operation.

The most common record types found in the DNS are:

  • "A" records - the mapping from a domain name to an IPv4 address
  • "AAAA" records - the mapping from a domain name to an IPv6 address
  • "MX" records - the mapping from a domain name to the host name of an SMTP server
  • "NS" records - used to delegate a portion of the hierarchy to specific DNS servers
  • "PTR" records - typically used (via in-addr.arpa.) to map an IPv4 address back to a domain name
  • "CNAME" records - used to alias a domain name to its canonical version

DNS packets are conventionally transported over UDP and TCP port 53. UDP is more commonly used, but larger DNS responses and zone transfers require TCP. See RFC 5966.

This Wikipedia article provides an approachable introduction to DNS.

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Ubuntu SOCKS proxy setup with two interfaces - how to pass DNS

I setup a SOCKSv5 server (Dante) on Ubuntu with two ethernet interfaces: eth0 is connected to my WAN with a static routable IP eth1 is connected to my LAN with a private IP I have a client connected on the LAN, and I'm able to ping the LAN port…
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DNS Server address configured inside Router not working

Well, I have an ISP router in which I have configured DNS Servers to use (Primary & Secondary) like Google DNS. It works just fine. But now I have setup a computer with DNS server (Simple DNS Plus). I got it working by settings my internal DNS…
Charandeep Singh
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DNS naming convention for multi-homed devices

Is it bad practice to have multiple IPs resolve via reverse DNS to the same hostname? Consider a router with multiple interfaces: 1 WAN and 3 separate LANs. Is it appropriate for all four IPs resolve to router.domain.com, or should the WAN interface…
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Using DNS entries to determine location

I'm trying to think of a clean way to determine the location of machines (mainly, which datacenter they belong to) based on their network settings. I would like it to be dynamic, and I'm thinking of using special DNS records that would be specific…
raphink
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nslookup Failure

I'm trying to figure out why nslookup can't find a local host name. CONFIGURATION I'm trying to setup an authoritative nameserver, working from "DNS and BIND", running bind9, on Debian 5.0, in a chroot "jail". bind seems to start okay, as there are…
chernevik
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TP-Link routers send DNS queries to 1.0.0.19. What is that?

I've got a problem with TP-Link soho routers. The DNS forwarder of those routers tends to ignore the DNS servers obtained by DHCP and instead tries sending all DNS requests to this strange IP: 1.0.0.19? That IP doesn't respond. Has anyone else seen…
facha
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Problem with the hosts file in Windows XP

I have a computer with Windows XP SP2 with a weird problem. The hosts file doesn't work. No matter what I do, adding or removing entries in the file doesn't make any difference, pinging the added names times out. I tried flushing the DNS cache…
Mee
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Local domain DNS resolution not working using OpenVPN on a pfSense box

I am currently trying to setup an OpenVPN server with the intention of linking several servers together in order to run the backup jobs over the VPN. For this example, this is what I have: A pfSense server running OpenVPN (pfsense.vpn) Two clients:…
Aron Rotteveel
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Nameserver can't be resolved globally. Server has been down for 30 hours

My server is under domain botoholic.com. I've started a dedicated hosting plan with the company Superhost.pl in Poland. My domain provider is Namecheap.com and my DNS is configured on the dedicated server with following…
blackd0t
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Computer settings in group policy are not applying...User settings applied easily..how?

We have a in house domain controller (DC1.xyz.local) & child domain controller (cdc1.abc.xyz.local)...I have below mentioned problems - None of the computer settings getting applied on to any of the computers.Tried lots of things on computer…
Rushikesh Gajare
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Wide Area Bonjour using DNS SRV Records

Running Apple's Lion Server (10.7.3). I am trying to get VPN clients (clients on another subnet) to see the server's Apple File share. I know that Bonjour doesn't route over a VPN or subnet, so I am adding static DNS entries. AFP shares work, as I…
Josh
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PowerDNS and a strange NXDomain

Allow me first to set the scene. We used to use Bind9, but ditched it in favour of PowerDNS, because, frankly, Bind sucks. We have a "primary" zone in our DNS master. london.wibblesplat.com There's other zones too, oob.london.wibblesplat.com The…
Tom O'Connor
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Regional DNS service names

So, here's the scenario: In our environment (Windows 2003 domain) we have a host X in production and X's twin in DR (call it Y). In the current version there is a CNAME abc that points to X. Problem is, what I really want is that Prod-site hosts…
Vincent Magnotta
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How to correctly set up DNS with custom name servers and IIS for multiple domains

I just obtained a Windows Server 2008 VPS. Rightly or wrongly I followed instructions from the host to set up custom name servers. So now I have ns1.mydomain.com and ns2.mydomain.com. The are both the same since I have 1 IP address. I have A…
nportelli
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Upgrading Zerigo DNS plan through Heroku failure

I'm hosting an app on Heroku and have a basic DNS plan with Zerigo. I tried to upgrade the Zerigo plan from "basic" to "tier 1" through the Heroku command line tool and received the following error: Hostname may not be assigned to both a CNAME and…
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