How to Configure DHCP In Linux (Ubuntu Server)?

Part 1:

Here is the capture of dhcp.conf file that was created when dhcp package was installed, after these commands added which satisfy the IP pool range, default and max lease time, subnets etc. Ive also attached dhcp config file with this document.


At the point when a DHCP client system connects to the network, dhclient requests a lease from the DHCP server and designs the client’s network interface(s). When a DHCP client has asked for and built up a lease, it stores data about the lease in a record named dhclient.leases, which is put away in the/var/lib/dhclient directory. This data is utilized to restore a lease when either the server or the client needs to reboot. The DHCP client setup document,/and so forth/dhclient.conf, is required just for custom configurations. The accompanying dhclient.conf document determines a solitary interface, eth0:

interface “eth0”
send dhcp-client-identifier 1:AA:B1:C2:D4:55:12;
send dhcp-lease-time 10800;


Part 2:

In part two I used the command tcpdump, utilizing packet sniffing functionality of LINUX.

The command: sudo tcpdump –c 30 –i eth0 (where 30 can be the n i.e. number of packets you want to capture)

Here are the screens:



The strategy for utilizing Tcpdump and gives numerous intriguing approaches to see top sources and destinations, and additionally methods for seeking text based network traffic. Additionally talked about was examination of edge case traffic situations that are outside what may be viewed as “ordinary” in DNS traffic, HTTP techniques and User-Agent strings. Fundamentals of creating and utilizing a pcap archive as laid out will assist you with building a base of network traffic to use for examination, or to set up a pattern for later correlation. These techniques depend on free programming and require no readiness outside of capturing the traffic and having a Linux/UNIX Bash at the examiner’s transfer. An included advantage is that these are totally free and promptly accessible utilities accessible to almost every Linux dispersion.

30 packets were captured, zero were dropped and all were from telling with length 46.

At the point when tcpdump completes the process of capturing bundles, we can see over that these things can be plainly seen i.e. 30 parcels “captured” which is the quantity of bundles that tcpdump has gotten and handled; parcels “received by channel” (the which means of this relies on upon the OS on which you’re running tcpdump, and potentially in transit the OS was arranged – if a channel was determined on the charge line, on a few OSes it tallies parcels paying little respect to whether they were coordinated by the channel expression and, regardless of the possibility that they were coordinated by the channel expression, paying little respect to whether tcpdump has perused and prepared them yet, on different OSes it checks just parcels that were coordinated by the channel expression paying little respect to whether tcpdump has perused and prepared them yet, and on different OSes it checks just parcels that were coordinated by the channel expression and were prepared by tcpdump); parcels “dropped by part” this is the quantity of parcels that were dropped, because of an absence of cushion space, by the bundle capture instrument in the OS on which tcpdump is running, if the OS reports that data to applications; if not, it will be accounted for as 0.

Diary (Problems Encountered & Solutions):

  • In order to successfully configure and run the server,
  • First you need to install dhcp, that can simply be installed using sudo apt-get
  • If the package doesn’t exist and dhcp is not downloaded, goto ubuntu sources and select the one containing dhcpd.
  • Simple write the url to the package in terminal to add the resource.
  • When the resource is added, its best to update the resource cache using sudo apt-update
  • We also require deb to get some repositories. If deb is not available, you can get dab or deb3 as well.
  • After updating the cache
  • Using quilt package
  • Get the sysv-cv — command running
  • You dont need sysv-cv command, if you can run chkconfig.
  • Now using vi commands start the server.
  • It took me almost more three hours to complete the tasks and counter the problems.


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