dnsmasq – use with Network Manager.

Well if you have not heard about dnsmasq:

Dnsmasq is lightweight, easy to configure DNS forwarder and DHCP server.
It is designed to provide DNS and, optionally, DHCP, to a small network.
It can serve the names of local machines which are not in the global
DNS. The DHCP server integrates with the DNS server and allows machines
with DHCP-allocated addresses to appear in the DNS with names configured
either in each host or in a central configuration file. Dnsmasq supports
static and dynamic DHCP leases and BOOTP for network booting of diskless
machines.

Continue reading

lightweight pdf viewer – zathura.

Zathura is a lightweight viewer for pdf which works on plugins. Here is shor description :

Zathura is a highly configurable and functional PDF viewer based on the Poppler
rendering library and the GTK+ toolkit. The idea behind zathura is an
application that provides a minimalist and space saving interface as well as
an easy usage that mainly focuses on keyboard interaction.

But the viewer will not work unless you install the plugins to display the correct plugin. So, if you want to use it for any real purposes then you will have to install the appropriate plugin as well, so here is what you need to do:

dnstop – top like utility for Fedora and other *nix

For installation :

sudo yum install dnstop

And now some description:

dnstop is a libpcap application (ala tcpdump) that displays various
tables of DNS traffic on your network.

dnstop supports both IPv4 and IPv6 addresses.

To help find especially undesirable DNS queries, dnstop provides a
number of filters.

dnstop can either read packets from the live capture device, or from a
tcpdump savefile.

Couple of days back, I realized there was too much network activity on my
system, although I was not doing anything. Fired up wireshark and to my
astonishment, there was too much of DNS traffic on the network. But the
problem was analyzing the data in wireshark and this is where dnstop came
into light. It helped me narrow down the issue within minutes and problems
resolved.

Disable a few cores when you want to save power.

If you have a lot of CPU power and working on battery. If you do not need that much of power and would like to rather save some battery power by disabling some cpus then you can use the below script. This script disables cpus from 4 to 7. You can change the number in the for loop. You would need the sudo to be setup or remove sudo and run the script as root. The script will show you the currently active cpu’s before and after disabling the CPU’s.

Battery performance improvement with powertop and using xidel.

For those of you, who have not heard about powertop, it is a tool to monitor the power consumption on your system. It has a tab which shows the tuneable parameters. Doing the changes suggested in those would improve the life to quite an extent. Here is the description of powertop:

PowerTOP is a tool that finds the software component(s) that makeyour computer use more power than necessary while it is idle.

Continue reading

Allow incoming/outgoing ports on iptables

Last couple of years, I just used to disable iptables on my system, this time I decided not to disable it and keep it enabled.

So far so good, now comes the tricky part, I have http server enabled on my system and since this is on local network with already firewall and other security in place so I can allow all incoming to my system and similarly I need to enable XDMCP outgoing. So, I can add the rules like this :

Xnest – XDMCP protocol and virtual DM

XDMCP is protocol that allows remote connections and provides you with a working Display Manager like KDE, GNome, et al. Its a remote connection protocol that is mostly enabled on Solaris and disabled on most Linux boxes. If you need to have a remote session where you need the X Display to open some GUI applications then you can have a connection with the remote server with XDMCP.