One question, why is this not enabled by default in Ubuntu, what is the downside?

Can the DNS entries become corrupt, and how long are the tables maintained?

Great tip though!

; <> DiG 9.5.1-P2 <> http://www.youtube.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48259
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;www.youtube.com. IN A

;; ANSWER SECTION:
http://www.youtube.com. 86400 IN A 88.255.41.21

;; AUTHORITY SECTION:
youtube.com. 86400 IN NS ns.company.lan.

;; Query time: 2014 msec
;; SERVER: 192.168.2.1#53(192.168.2.1)
;; WHEN: Sat Aug 29 10:15:13 2009
;; MSG SIZE rcvd: 77

mustafa@mustafa-desktop:~$ dig http://www.youtube.com

; <> DiG 9.5.1-P2 <> http://www.youtube.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22587
;; flags: qr rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;www.youtube.com. IN A

;; ANSWER SECTION:
http://www.youtube.com. 10000 IN A 88.255.41.21

;; Query time: 2 msec
;; SERVER: 192.168.2.1#53(192.168.2.1)
;; WHEN: Sat Aug 29 10:15:15 2009
;; MSG SIZE rcvd: 49

great little tutorial, however I think everyone with no firwall between them and the net should know this:

Supposing you only have one interface open to the internet (IE eth0)

If you state in your config “listen-adress=127.0.0.1″ you would kinda expect it to do exactly that.

however running this reveals that it has opened a TCP port on your eth0:

(Great if you wanna speed things up on your LAN for others, but not for me)

To see what its doing on run:

$ netstat -ant | grep :53
tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN
tcp 0 0 {YOUR ETH0 IP}:53 {YOUR ETH0 IP}:47167 TIME_WAIT

I want that port DEAD, and i’m not gonna use a firewall to do what software should control.. so…

I fiddled with some of the settings in dnsmasq.conf like:

except-interface=eth0
interface=lo

But still this didn’t work.., nmap could still see something running :

$ nmap {YOUR ETH0 IP} -p 53 -A

Starting Nmap 4.20 ( http://insecure.org ) at 2008-11-17 03:51 GMT
Interesting ports on ({YOUR ETH0 IP}):
PORT STATE SERVICE VERSION
53/tcp open tcpwrapped

-----

I’m sure its not a big thing but i’m a paranoid perfectionist…

Anyway all it needed to actually completely ignore eth0 is:

interface=lo
bind-interfaces

========= Viola !!!========

$ nmap {YOUR ETH0 IP} -p 53 -A | grep 53
53/tcp closed domain

$ netstat -ant | grep :53
tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN

$ sudo lsof | grep dnsmasq | grep :
dnsmasq 27561 dnsmasq 5u IPv4 155191 TCP localhost:domain (LISTEN)
dnsmasq 27561 dnsmasq 6u IPv4 155192 UDP localhost:domain
dnsmasq 27561 dnsmasq 9u IPv4 155201 UDP *:37795

Hope this helps

It makes an enormous difference over satellite, where each request is a two second round trip

Thanks a lot

Cheers!

BUT - people like myself who live in outback nowhere, and rely on unreliable ISP´s, with unreliable DNS servers can realize a tremendous saving in time. It was not unusual for me to wait several seconds, just to read a message that an address couldn´t be found. Preposterous, that I can open maybe 6 tabs on a given site, and the seventh address can´t be found!!

Running your own DNS cache and/or DNS server can make the difference between enjoying your time online, or just giving up, out of frustration.

Yes this should be standard on Ubuntu desktop

I can’t disagree more strongly with Dan’s cynicism (comment 1 above). He clearly doesn’t understand the aggregating problems of network latency nor that DNS sometimes hiccups and goes slowly for the odd second (or so it seems to me). And that’s for wired people - not putting up with satellites etc (comment 7 above).

The local dnsmasq cache solves these problems. I agree with the suggestion that this should be standard on Ubuntu desktop.

I read a lot of complaints about poky web-browing with Firefox in ubuntu, they should really have this as a standard inclusion on all installations. New users especially will be put out by slow web-browsing when they try the system on a livecd or experimental installation.

First time - dig yahoo.com - Query time: 114 msec

Second Time - Same address - Query time: 4 msec

Change
“uncomment the following line (remove “#” in the beginning) in the file /etc/dnsmasq.conf”

To
Open a text editor and type

sudo gedit /etc/dnsmasq.conf

“Add after “listen-address=” 127.0.0.1

At least in my case I couldn’t find the referenced entry. All I found was “listen-address=” on line 73 of gedit of /etc/dnsmasq.conf

Same with all after “Now edit”

sudo gedit /etc/dhcp3/dhclient.conf

Thank you for writing the tutorial I saw a dramatic improvement also.

BTW, I just did this and my speed went from 15ms to 0ms.

I have corrected now thanks for your correction

One /tiny/ correction though: there is an extra period at the end of
”
sudo /etc/init.d/dnsmasq restart.
”

Thanks again.

you saved yourself a 1/3 of a blink