HowFlow


NetworkingCategory: Networking | Tags: kde konqueror pdnsd cache nameserver comments 0 Comments
HowFlow — Konqueror is my favourite web browser, but it has one problem: it isn't the fastest browser on earth. Follow this step by step guide to speed it up.
Share it!   Posted by Avatar flood 7 months ago

Problem

Konqueror makes a lot of DNS requests, because it lacks a DNS cache. Every time you click on a link on the same page, it asks the name server again and again the same requests. Let’s have a look at the tcpdump output:


hydra linux # tcpdump -i wlan0 port 53 | grep kde
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlan0, link-type EN10MB (Ethernet), capture size 96 bytes
03:51:37.814131 IP noname.47046 > fritz.fonwlan.box.domain: 62453+ A? www.kde.org. (29)
03:51:37.815315 IP noname.46355 > fritz.fonwlan.box.domain: 12266+ AAAA? www.kde.org. (29)
03:51:37.818689 IP fritz.fonwlan.box.domain > noname.47046: 62453 1/3/3 A jamaica.kde.org (147)
03:51:37.827959 IP noname.55171 > fritz.fonwlan.box.domain: 34759+ AAAA? www.kde.org. (29)
03:51:38.153790 IP noname.54649 > fritz.fonwlan.box.domain: 59581+ A? www.kde.org. (29)
03:51:38.154227 IP noname.45932 > fritz.fonwlan.box.domain: 1783+ AAAA? www.kde.org. (29)
03:51:38.154527 IP noname.35916 > fritz.fonwlan.box.domain: 63272+ A? www.kde.org. (29)
03:51:38.154703 IP noname.34958 > fritz.fonwlan.box.domain: 40719+ AAAA? www.kde.org. (29)
03:51:38.155532 IP noname.48468 > fritz.fonwlan.box.domain: 29074+ A? www.kde.org. (29)
03:51:38.155786 IP noname.53167 > fritz.fonwlan.box.domain: 6327+ AAAA? www.kde.org. (29)
03:51:38.158576 IP fritz.fonwlan.box.domain > noname.54649: 59581 1/3/3 A jamaica.kde.org (147)
03:51:38.160777 IP fritz.fonwlan.box.domain > noname.35916: 63272 1/3/3 A jamaica.kde.org (147)
03:51:38.165405 IP fritz.fonwlan.box.domain > noname.48468: 29074 1/3/3 A jamaica.kde.org (147)
03:51:43.155083 IP noname.45932 > fritz.fonwlan.box.domain: 1783+ AAAA? www.kde.org. (29)
03:51:43.155317 IP noname.34958 > fritz.fonwlan.box.domain: 40719+ AAAA? www.kde.org. (29)
03:51:43.156320 IP noname.53167 > fritz.fonwlan.box.domain: 6327+ AAAA? www.kde.org. (29)
03:51:48.155660 IP noname.45102 > fritz.fonwlan.box.domain: 22557+ AAAA? www.kde.org. (29)
03:51:48.156134 IP noname.35483 > fritz.fonwlan.box.domain: 7088+ AAAA? www.kde.org. (29)
03:51:48.157225 IP noname.50214 > fritz.fonwlan.box.domain: 3819+ AAAA? www.kde.org. (29)
03:51:53.155423 IP noname.45102 > fritz.fonwlan.box.domain: 22557+ AAAA? www.kde.org. (29)
03:51:53.157183 IP noname.35483 > fritz.fonwlan.box.domain: 7088+ AAAA? www.kde.org. (29)
03:51:53.158334 IP noname.50214 > fritz.fonwlan.box.domain: 3819+ AAAA? www.kde.org. (29)
03:51:58.407589 IP noname.46900 > fritz.fonwlan.box.domain: 27649+ A? www.kde.org. (29)
03:51:58.407952 IP noname.50877 > fritz.fonwlan.box.domain: 40260+ A? www.kde.org. (29)
03:51:58.408142 IP noname.43841 > fritz.fonwlan.box.domain: 65416+ AAAA? www.kde.org. (29)
03:51:58.408324 IP noname.35139 > fritz.fonwlan.box.domain: 626+ AAAA? www.kde.org. (29)
03:51:58.409119 IP noname.40596 > fritz.fonwlan.box.domain: 5619+ A? www.kde.org. (29)
03:51:58.409306 IP noname.56401 > fritz.fonwlan.box.domain: 15192+ AAAA? www.kde.org. (29)
03:51:58.412438 IP fritz.fonwlan.box.domain > noname.46900: 27649 1/3/3 A jamaica.kde.org (147)
03:51:58.413405 IP fritz.fonwlan.box.domain > noname.50877: 40260 1/3/3 A jamaica.kde.org (147)
03:51:58.419296 IP fritz.fonwlan.box.domain > noname.40596: 5619 1/3/3 A jamaica.kde.org (147)
03:52:03.409085 IP noname.43841 > fritz.fonwlan.box.domain: 65416+ AAAA? www.kde.org. (29)
03:52:03.409320 IP noname.35139 > fritz.fonwlan.box.domain: 626+ AAAA? www.kde.org. (29)

As you can see, it asks my router (fritz.fonwlan.box) tons of questions. It would be nice to have a local DNS cache to reduce the number of DNS requests.

pdnsd to the rescue

Installation

pdnsd is a local DNS cache that reduces external DNS requests to a minimum. You can find it in the repository of your distribution. The installation is pretty simple:


# Ubuntu/Debian:

sudo apt-get install pdnsd

# Gentoo:

emerge pdnsd

Configuration

Depending on your distribution, the configuration file is located in different directories. Let’s open it in our editor of choice:


# Ubuntu/Debian:

gksudo gedit /etc/pdnsd.conf

# Gentoo:

nano -w /etc/pdnsd/pdnsd.conf

Here is my pdnsd.conf. It looks complicated, but I think, it is self-explaining:


global {
    perm_cache=2048;
    cache_dir="/var/cache/pdnsd";
    run_as="pdnsd";
    server_ip = 127.0.0.1;  # Use eth0 here if you want to allow other
                # machines on your network to query pdnsd.
    status_ctl = on;
    query_method=udp_tcp;
    min_ttl=15m;       # Retain cached entries at least 15 minutes.
    max_ttl=1w;        # One week.
    timeout=10;        # Global timeout option (10 seconds).
}

# The following section is most appropriate if you have a fixed connection to
# the Internet and an ISP which provides good DNS servers.
server {
    label= "floodnet";
    ip = 192.168.178.1;  # Put your ISP's DNS-server address(es) here.
    timeout=4;         # Server timeout; this may be much shorter
               # that the global timeout option.
    uptest=if;         # Test if the network interface is active.
    interface=wlan0;    # The name of the interface to check.
    interval=10m;      # Check every 10 minutes.
    purge_cache=off;   # Keep stale cache entries in case the ISP's
               # DNS servers go offline.
}

source {
    owner=localhost;
    file="/etc/hosts";
}

rr {
    name=localhost;
    reverse=on;
    a=127.0.0.1;
    owner=localhost;
    soa=localhost,root.localhost,42,86400,900,86400,86400;
}

Basically, you only have to change two lines in the first server section: the interface, which should be the external interface of your computer and the ip, which should point to the IP of your actual name server – for most people, it is the IP of your wireless router.

Starting pdnsd


/etc/init.d/pdnsd start

pdnsd should now listen to port 53:


hydra linux # netstat -ln
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 ::ffff:127.0.0.1:53     :::*                    LISTEN
udp        0      0 ::ffff:127.0.0.1:53     :::*

If all went well, we should now set the nameserver entry of /etc/resolv.conf to our new local DNS cache. It should look like this:


nameserver 127.0.0.1

Testing pdnsd

I’m doing the same request from the beginning of this trick twice. The first time I visit http://www.kde.org/, it fills the local DNS cache, but if I visit it the second time, no DNS requests are made to my router. Here is the tcpdump output:


hydra linux # tcpdump -i wlan0 port 53 | grep kde
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlan0, link-type EN10MB (Ethernet), capture size 96 bytes

As you can see, there were no DNS requests made. The second page reload took just a fraction of the time of the first load.

You should now add pdnsd to your standard runlevel.

For more Linux tricks, click here



Please log in or sign up and vote for this trick if it was helpful for you.
Don't forget to subscribe to our RSS Feed RSS/Atom feed to get the latest tricks.
Imprint | Powered by Ruby on Rails