DNS stands for the Domain Name System, a hierarchical, distributed database where the keys are domain names.
9
votes
6answers
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How to use DNS/Hostnames or Other ways to resolve to a specific IP:Port
This is a Canonical Question about DNS/Hostnames resolution to IPs/Ports
Example 1
I'm running a web server on port 80 and another on port 87. I would like to use DNS so that www.example.com ...
48
votes
2answers
51k views
How to Configure Windows Machine to Allow File Sharing with DNS Alias
What process is necessary to configure a Windows environement to allow me to use DNS CNAME to reference servers?
I want to do this so that I can name my servers something like SRV001, but still have ...
73
votes
15answers
58k views
Why is DNS failover not recommended?
From reading, it seems like DNS failover is not recommended just because DNS wasn't designed for it. But if you have two webservers on different subnets hosting redundant content, what other methods ...
20
votes
3answers
3k views
46
votes
20answers
15k views
Hosting your own DNS
I currently have my ISP providing DNS for my domain, but they impose limitations on adding records. Therefore, I am thinking about running my own DNS.
Do you prefer to host your own DNS, or is it ...
33
votes
23answers
5k views
Who is a good registrar these days? [closed]
It's been a long time since I've had to register a new domain.
What registrar is considered geek and sysadmin friendly?
I've heard that godaddy will screw you 10 ways to Sunday, and a lot of the ...
37
votes
14answers
19k views
Top level domain for private networks?
On our office network we have an internal DNS and all the hostnames are whatever.lan. On my VMware VMs, on their host-only network I call them whatever.vm.
We now have a private IP space network in ...
4
votes
5answers
4k views
How can I automaticaly change the DNS A record to point my site to a secondary server in case of a failure?
My hosting is charging me a $50/month fee to put my servers on the same VLAN so that I create a cluster using the Network Load Balancing feature.
I'm really not needing split the load between the ...
6
votes
1answer
1k views
In DNS can an IN NS point to a CNAME?
Is it allowed to have an NS record be a CNAME? E.g.:
subdomain.example.com. IN NS ns1.example.com.
ns1.example.com. CNAME foo.example.com.
foo.example.com. IN A ...
44
votes
15answers
6k views
Are IP addresses “trivial to forge”?
I was reading through some of the notes on Google's new public DNS service:
Performance Benefits
Security Benefits
I noticed under the security section this paragraph:
Until a standard ...
20
votes
5answers
11k views
Geo-DNS providers? [closed]
We've got a website visited by users mainly in the USA and UK. The site will be run on servers in both these locations.
We would like to use a DNS service to direct users to the nearest server, but ...
34
votes
8answers
28k views
Is a wildcard CNAME DNS record valid?
I know it's valid to have a DNS A record that's a wildcard (e.g. *.mysite.com). Is it possible/valid/advised to have a wildcard CNAME record?
42
votes
10answers
9k views
Multiple data centers and HTTP traffic: DNS Round Robin is the ONLY way to assure instant fail-over?
Multiple A records pointing to the same domain seem to be used almost exclusively to implement DNS Round Robin as a cheap load balancing technique.
The usual warning against DNS RR is that it is not ...
29
votes
4answers
2k views
Why does DNS work the way it does?
This is a Canonical Question about DNS (Domain Name Service).
If my understanding of the DNS system is correct, the .com registry holds a table that maps domains (www.example.com) to DNS servers.
...
17
votes
15answers
15k views
Is Round-Robin DNS “good enough” for load balancing static content?
We have a set of shared, static content that we serve up between our websites at http://sstatic.net. Unfortunately, this content is not currently load balanced at all -- it's served from a single ...
26
votes
1answer
22k views
How long does it take for DNS records to propagate?
This is a Canonical Question 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 ...
9
votes
4answers
6k views
Set root domain record to be a CNAME
I need to create an NS record for a domain that is a CNAME, for the purpose of having two domains pointed at one IP, and not having to maintain the current IP address in two different places.
The DNS ...
54
votes
22answers
8k views
How the heck is http://to./ a valid domain name?
Apparently it's a URL shortener. It resolves just fine in Chrome and Firefox. How is this a valid top-level domain?
Update: for the people saying it's browser shenanigans, why is it that: ...
15
votes
4answers
6k views
Reverse DNS in a CIDR world
Reverse DNS seems to be strongly tied to class boundaries, what methods exist now that CIDR is the standard to delegate authority for a subnet? If multiple methods exist which one is best? Do you ...
5
votes
10answers
649 views
Is there a good overview of the DNS system?
I want to get an understanding of how the DNS system works. How domain names actually get resolved and how admins setup a domain name so it is resolved correctly to a target machine.
The sources you ...
2
votes
4answers
336 views
What is the correct behaviour when Nameservers Change
I have been having some issues with a certain network supplier over unchanged nameservers making my site invisible to their customers. I wouldnt be bothered except that they are one of the largest ...
11
votes
6answers
14k views
Overriding some DNS entries in BIND for internal networks
I have an internal network with a DNS server running BIND, connected to the internet through a single gateway. My domain "example.com" is managed by an external DNS provider. Some of the entries in ...
5
votes
5answers
10k views
How do I configure SPF for multiple domains on a server? (also allowing gmail as a sender)
SPF (Sender Policy Framework) seems like a good way to combat spammers/spoofing.
However, despite reading the explanations several times, I'm not quite understanding how to configure it correctly.
...
8
votes
12answers
6k views
Using .local for internal websites
Is it okay to use app.mycoolname.local for URLs that are private / internal?
We have several applications that are web based, but they are private apps and are not exposed to the public.
We have ...
7
votes
3answers
4k views
Wildcard DNS and subdomains
Let'say that i've got the domain mydomain.com.
I want that when any visitor goes to
www.mydomain.com
xyz.mydomain.com
abc.mydomain.com
asd.mydomain.com
qwe.mydomain.com
etc...
the visitor will ...
3
votes
5answers
1k views
How do I move my website to a new server without interruption to email?
I have a corporate website on a server that also hosts all our email. I have no idea how diligent all the employees have been about backing up their email / leaving old messages on the server, etc. In ...
3
votes
3answers
234 views
Website hosting from home - IIS6
I'm wanting to host a few websites from home, primarily because I'm using some BETA Microsoft software (.NET 4 and EF) and don't want to install it on my production server which is hosted at ...
3
votes
5answers
1k views
Enable access without “www.” on Ubuntu
I want to enable the access to my site without the "www." prefix. I tried to insert this in my /etc/apache2/sites-available file:
<VirtualHost *:80>
serverName mydomain.gov.br
...
2
votes
1answer
163 views
My visitors %20 percent can't reachable to my web site
i have dedicated web server and also i hosting www.btgmaslak.com web site. I'm facing a problem about 1 days. My visitors about 20 percent can't reach my web site. I thing this problem occurs because ...
1
vote
1answer
472 views
No-ip works for non-internal clients, pinging works internally
I'm having a really bizarre problem while using No-IP. I can access the server fine from clients not on the local network and local and remote clients can ping the server just fine. I get the same ...
0
votes
3answers
2k views
Configure DNS server to return same IP for all domains
I would like to configure a nameserver that will return the same IP address ("A" record) for any arbitrary host name. For example:
example.com
subdomain.example.com
someotherdomain.com
...
22
votes
2answers
3k views
Why does Heroku warn against “naked” domain names?
I ran across this page in the Heroku docs...
Naked domains, also called bare or apex domains, are configured in DNS via A-records and have serious availability implications when used in highly ...
9
votes
3answers
3k views
What's the meaning of '@' in a DNS zone file?
I have the following data in my dns file, for my domain...
$ORIGIN mydomain.com.
@ IN A 208.X.Y.Z
mail IN A 208.X.Y.Z
... etc..
what is the @ line, mean? I know what ...
9
votes
2answers
771 views
Apache: Scammers point dozens of domain names at my dedicated IP. How to prevent this?
For the sake of discussion, pretend that I have an Apache webserver which serves a website at www.example.org. This domain name resolves to the public IP address at 192.168.1.100 (pretend this is a ...
8
votes
3answers
13k views
How to create a CNAME for a domain's root name
I'd like to set a domain's root name to a CNAME instead of the usual A record.
Here's a perfect example of what I'm trying to do:
dig lrnskls.com
Notice the answer section:
;; ANSWER SECTION:
...
7
votes
4answers
21k views
How to find all hostnames in DNS attached to one IP?
If I have multiple hosts configured on one machine (a la apache's VirtualHosts), how can I do a lookup on the IP and find all domains configured to reach it?
For example, I have several web and email ...
6
votes
2answers
397 views
Is there anything I can do about someone who has pointed their domain at my ip?
This is kind of a weird request. For some reason whoever owns safeandbuy.com has pointed their domain at my IP address. The reason it's a problem is that I'm having all kinds of crawlers that are ...
6
votes
3answers
12k views
How exactly should I set up DNS to delegate authority for subdomains?
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 ...
4
votes
8answers
3k views
Why is it called DNS “Propagation”?
I always hear system administrators talk about waiting for DNS records to propagate "around the Internet" or "around the world" when they talk about making DNS changes. The fact of the matter is that ...
5
votes
2answers
2k views
hosts file seems to be ignored
I have almost fresh Ubuntu desktop box. OS was installed two weeks ago and updated from karmic repositories. Last week I had no problems with DNS. But this week something had changed. I'm not sure ...
4
votes
5answers
3k views
Active Directory: Is it required that the “A” record for a domain point to a Domain Controller?
Currently we have an Active Directory setup, and say the name is 'domain.com'. The DNS entries for domain.com has two A records pointing to the two domain controllers. I would like internal users to ...
0
votes
6answers
6k views
Why should one have a secondary DNS server?
I'm very confused.
I basically understand how DNS works. Here's an example that helps illustrate what I'm having trouble understanding.
Right now, I run a small web-server. I use my provider's DNS ...
11
votes
2answers
1k views
Who actually “recurses” in a recursive DNS lookup?
I'm trying to understand the difference between iterative and recursive DNS lookups. Fundamentally, I think of iterative as being like calling a department store looking for a product, and when they ...
7
votes
5answers
4k views
How important are PTR records for Email Servers?
Does anyone know of any studies done to show how much email will be rejected if there is not ptr record for the SMTP banner name of an email server?
Are reverse checks always done when enabled, or ...
3
votes
6answers
6k views
Why aren't our DNS records propagating out into the internet?
We run the name servers for our domain on our network. We use bind/named. Lets call the domain jokerville.com. One thing I've noticed recently, when I goto a website like http://network-tools.com and ...
1
vote
3answers
785 views
Multiple domains on Amazon AWS EC2
I am a bit confused on how I can use Amazon AWS to host multiple websites. I under stand how to host a website on there however I am only allowed up to 5 elastic ip addresses. So how would I host more ...
0
votes
5answers
139 views
Many domains/sites hosted on same server, CNAME alternatives to avoid writing same IP in DNS?
I have many sites (each one with its own domain) all on the same cPanel hosted server (let's say server IP is 1.1.1.1 and server main domain is myserver.com)
All these domains use third party DNS ...
0
votes
7answers
1k views
Is it possible to have regular-expression CNAME record in DNS?
Is it possible to do something like this? Or any equivulent? in a DNS server.
([0-9]{2}).mydomain.com. IN CNAME www$1.other-domain.com.
-3
votes
2answers
1k views
How browsers handle multiple IPs
Can someone direct me to information on exact browsers behavior when browser gets multiple A records for a given hostname (say ip1 and ip2), and one of them is not accessible.
I interested in EXACT ...
18
votes
5answers
2k views
Free service for checking for DNS errors on your domain?
Is there a free service for checking for common DNS errors on your domain? I previously used dnsstuff.com for this, but they since moved to a paid model.
