Domain Name System for computers, services, or any resource connected to the Internet. It translates domain names meaningful to humans into the numerical identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide.

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56
votes
10answers
59k views

How do I clear the DNS cache?

I just updated the DNS record (ns1, ns2, ns3.myhostingcompany.com) for a site I've got hosted, but I still get the domain registrar parking page. I'd like to see if the problem is Ubuntu's cached DNS ...
38
votes
5answers
91k views

Command-line to list DNS servers

Is there a command to list dns servers? I tried $ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR ...
28
votes
4answers
37k views

NetworkManager not populating resolv.conf

I recently upgraded from 11.10 to 12.04, and now NetworkManager isn't populating /etc/resolv.conf when connecting to wireless networks, when it had been working perfectly in 11.10. I'm not seeing any ...
28
votes
2answers
22k views

How do I get resolvconf to regenerate resolv.conf after I change /etc/network/interfaces?

After updating /etc/networking/interfaces with something very similar to below, how do I get /etc/resolv.conf to update? I tried (as root) resolver -u, service networking restart but they didn't ...
28
votes
6answers
5k views

Problem resolving many of the Web Pages

I am presently running Ubuntu 12.04 and using Chrome/Firefox along with OpenDNS (have tried Google Public DNS as well as DNS of my ISP). Suddenly, a lot of websites that I visit frequently don't ...
23
votes
8answers
31k views

What is the proper way to change the DNS IP?

I suspect that the name server provided by my ADSL modem/router is buggy. Whenever I browse to a website for the first time in ubuntu, resolving the domain name takes at least 15 seconds. To work ...
23
votes
5answers
5k views

Virtualbox DNS stopped working on upgrade to 12.10

I have a Debian image setup on Virtualbox that uses the default NAT to access the internet. It was working fine before I upgraded to 12.10. After I upgraded the DNS lookups no longer work. I still can ...
20
votes
6answers
14k views

What Can Be Done To Secure Ubuntu Server?

I have a project to secure Ubuntu Server as much as I can. The server is a web hosting server. The server will be running LAMP , Mail , and DNS.
17
votes
4answers
59k views

How do I edit my resolv.conf file to fix wrong DNS problem?

I have the problem that my Ubuntu machine uses the wrong DNS server. For some reason the machine queries localhost for DNS information. I have added the DNS server in the network settings GUI, but ...
17
votes
4answers
24k views

resolv.conf doesn't get set on reboot when networking is configured for static ip

I'm experiencing what appears to be a name resolution issue in Ubuntu 12.04 Server edition when configuring my computer to use static ip. In /etc/network/interfaces: # The primary network interface ...
16
votes
6answers
118k views

How do I configure my static DNS in interfaces?

I am using Ubuntu 12.04. My /etc/network/interfaces file consists of: # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface ...
15
votes
2answers
1k views

Route complete TLD (*.dev for example) to 127.0.0.1

For development purposes I want all DNS requests to the .dev TLD to forward to my own PC. The hosts file does not suffice. I use multiple domains and also multiple subdomains. I would have to add a ...
15
votes
2answers
6k views

Switching a server to static IP from DHCP

I am running an Ubuntu 10.04 server installation and I recently had to switch it from DHCP to static ip. I edited /etc/network/interfaces file and switched iface eth0 inet dhcp to iface eth0 inet ...
15
votes
7answers
8k views

Why does my resolv.conf file get regenerated every time?

My /etc/resolv.conf file gets regenerated every time, making me loose Google DNS servers when I reconnect my 3G modem. For changing the DNS settings, I looked at ...
14
votes
3answers
18k views

How to know what DNS am I using in Ubuntu 12.04

We used to get current DNS settings by: cat /etc/resolv.conf But Ubuntu 12.04 has changed to use the resolvconf framework. The above commond will only give me this: # Dynamic resolv.conf(5) ...
14
votes
2answers
7k views

nslookup finds ip, but ping doesnt

I know this looks like all the other "can ping via ip but not dns" questions, but those didnt really help me at all. Also, having hosts files in all machines is not doable as this server will ...
14
votes
2answers
386 views

Identify “rogue” internet accessing Applications

At the moment I have an application/service/widget/plugin/cronjob whatever, accessing the internet on a regular basis. I could go into the details of my specific issue but I'd rather have an answer ...
13
votes
5answers
8k views

Why can't my machine resolve local windows hostnames?

When I ping any local windows hostname from my Ubuntu machine I get "unable to resolve host", but when I ping from a windows machine it works fine. Why would this be? OS: Ubuntu 10.04 Samba & ...
11
votes
2answers
7k views

What does “.local” do?

I've got several Ubuntu machines on my network at home, but the DNS is provided by a windows server (2K). When I ssh to them from another , if I ssh to them as "machine" I can't connect, but if I ...
10
votes
3answers
11k views

DNS server address no longer stored in resolv.conf; where is it now?

I sometimes switch DNS servers, using the NetworkManager indicator in the taskbar; this worked fine with previous versions, and actually works fine with 12.04, too, except for one thing: I use Conky ...
10
votes
5answers
24k views

Best way to set up DNS caching?

In order to speed up DNS lookups, I want to install a DNS cache or proxy. I can see at least three programs I think will do the job: bind9, pdnsd, or dnsmasq. I would like to make sure that if I ...
10
votes
3answers
17k views

Prefer A (IPv4) DNS lookups before AAAA(IPv6) lookups

In notice my newly installed Ubuntu 10.10 always does an AAAA DNS lookup before A record lookups. Is there any way I can configure the system to do A lookups first ? (While various browsers and other ...
9
votes
4answers
5k views

Name resolution on home LAN?

Is there an easy way to allow my other computers to resolve my hostname over the network without having them edit their hosts files or their DNS settings? Some of the computers are on Windows.
9
votes
10answers
4k views

Can't browse the internet nor ping a host, but dig works

I am not able to browse any websites. Please take a look at the following error: karthick@karthick:~$ ping www.google.com ping: unknown host www.google.com Update ...
8
votes
2answers
22k views

How to use host names rather than ip addresses on home network?

I've a small home network up and running and managed to set up ssh. Can anyone tell me what I need to do to refer to one computer on the network from another by host name rather than IP address (which ...
8
votes
1answer
45k views

How do I configure my DNS settings in Ubuntu server?

According to this page it appears to be simple. However, /etc/bind does not exist on the default installation of Ubuntu 12.04.3 LTS server. So, without installing any further software, how can ...
8
votes
2answers
9k views

What is my DNS server?

My /etc/resolv.conf looks like this: # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver ...
8
votes
3answers
30k views

How to edit hosts.deny and hosts.allow?

I want to block some hosts in Ubuntu, so how could I edit hosts.deny file to block some hosts like example.com. And one more thing I have installed dnsmasq in Ubuntu, so can I check the entries of ...
8
votes
4answers
7k views

Slow DNS Resolution

After a clean install of 10.10 I'm finding DNS resolution takes quite a long time. Hitting any url takes a good few seconds (10 - 30) before the site is displayed. I'm thinking this is a DNS ...
8
votes
3answers
3k views

Virtualbox on Ubuntu Host: Access guests by hostname

I have several VirtualBox appliances (Windows, Linux) each of them configured with two network adapters: NAT for accessing the internet host-only for hosts <> hosts and hosts <> guest ...
8
votes
3answers
2k views

DNS sometimes works, but it is very slow.

I am having DNS problems since upgrading to Ubuntu 12.04 (Precise Pangolin) from Ubuntu 10.04 (Lucid Lynx) yesterday. DNS sometimes works, but it is very slow. I have read the blog post DNS in ...
8
votes
3answers
3k views

Cannot resolve custom domains when VPN is up

I just upgraded to 12.04 from 11.10, and now I can't resolve custom domains over my VPN (e.g. *.dev.local). It worked splendid before the upgrade. Both my /etc/resolv.conf and route -n looks exactly ...
8
votes
1answer
13k views

Why does my name resolution hit the DNS even with a hosts file entry?

I'm running Ubuntu 10.04.2 LTS Desktop. Being a web developer, naturally I created a "me.com" in my /etc/hosts file. Unfortunately, my name resolution is going out to the DNS before first checking my ...
7
votes
4answers
1k views

How to reach a host in the same network by hostname?

I have a network which connects a couple of hosts. I would like to be able to reach other hosts from one of them using the hostname. I just discovered the ".local" domain, which is available through ...
7
votes
1answer
1k views

Dynamic /etc/resolv.conf file?

I have several Ubuntu servers. Two of them are working as DNS servers. One of my name servers (let's call it DNS1) went down for maintenance. I sill had another DNS server running (DNS2). All other ...
7
votes
6answers
6k views

How to check if DNS is encrypted?

I have installed DNSCrypt , its OpenDNS encrypted DNS patch for Ubuntu & other Linux users & it's working fine. How do I know if my DNS is encrypted? I have googled but didn't find anything. ...
7
votes
3answers
947 views

From Ubuntu, “Back to my Mac”

I have a Mac at home, and run Ubuntu at work. I'd like to be able to connect to my Mac in a similar way to how I had when I worked on a Mac. I have MobileMe so I used Back to My Mac (Apple's version ...
7
votes
2answers
15k views

How can I host a domain/website on my new VPS?

I am an average Ubuntu user and currently i decided to strengthen my knowledge in Ubuntu. Since i am a web developer, lately i decided to setup my own web server powered by Ubuntu. I just bought an ...
6
votes
4answers
15k views

How to view the DNS address assigned by DHCP?

How to view the DNS address assigned by DHCP? ifconfig can not show it. $ ifconfig -a eth0 Link encap:Ethernet HWaddr 90:e6:ba:22:6a:f2 inet addr:192.168.1.111 Bcast:192.168.1.255 ...
6
votes
4answers
2k views

Why do I get redirected to a weird Chinese site for non-existent websites?

If I go to a web address that doesn't exist such as http://testestewcsdijncijfkdmkdfkddmkmdmdsexsecsecfvrgtoejwfej.com/ I get landed on a strange Chinese page like this: This happens for all web ...
6
votes
3answers
41k views

Editing dns-nameservers in /etc/network/interfaces without a restart [duplicate]

After editing dns-nameservers in /etc/network/interfaces, how do I tell resolvconf(8) to read the new value without restarting networking? (causing a service interruption) The -u option doesn't seem ...
6
votes
1answer
12k views

what does mean dns-seach option in /etc/network/interfaces

can anybody describe me about dns-search directive in /etc/network/interfaces file: iface eth0 inet static address 192.168.3.3 netmask 255.255.255.0 gateway 192.168.3.1 dns-search ...
6
votes
3answers
6k views

DNS resolution fails after 12.10 upgrade

After my upgrade to 12.10, DNS resolution seems to fail for both local and external addresses. I can successfully ping local and external IP addresses (google.com, at least), but pinging DNS names ...
6
votes
4answers
15k views

internet access problem in 12.04

Yesterday, I have upgraded Ubuntu from 11.10 to 12.04 LTS and everything was ok (there was no error) After restart, my "Auto Ethernet" connection established, also my VPN connection established.And ...
6
votes
1answer
640 views

Protecting against (infinitely) slow DNS servers

Recently, one of my ISPs DNS servers got into trouble. To quote the support desk personnel it "wasn't completely down so connections were just infinitely slow". My application was down for a couple of ...
6
votes
1answer
322 views

Network only using one DNS when connected to VPN

My company has a VPN that I need to connect to. In OSX, I do this by using openvpn with the following configuration: client dev tun proto udp remote <GATEWAY_ADDRESS> <PORT> resolv-retry ...
6
votes
1answer
2k views

How do I set up an Ubuntu server as a secondary DNS

The company I now work for specializes in web development. They are currently selling clients packages where they develop web applications for them to help automate certain business tasks for them. ...
6
votes
0answers
8k views

Network Manager discards changes to /etc/resolv.conf on boot [duplicate]

Possible Duplicate: How To Auto Add To /etc/resolv.conf? I wrote interfaces entries manually because of weird behaviour from network manager/indicator: $ cat /etc/network/interfaces auto ...
5
votes
2answers
29k views

How to flush dns in ubuntu 12.04? [duplicate]

how to flush dns of Ubuntu 12.04 LTS (GNU/Linux 3.2.0-23-generic x86_64) have tried many things form here and here also but nothing is working
5
votes
2answers
9k views

Not able to get the reverse DNS working

I had been struggling to get reverse DNS working using nslookup on Ubuntu 12.04. Here is the output of the nslookup command and the content of the different network related configuration files. What ...