dhtest readme

About the tool

dhtest - linux dhcp client simulation tool. It can simulate hundreds of dhcp client from a linux machine. Linux root login is needed because the tool requires layer2 raw socket for sending and receiving dhcp packets.

Installation

* Download the latest source from github as zip. 
  Download link - https://github.com/saravana815/dhtest/archive/master.zip

    [sargandh@CentOS Desktop]$ unzip dhtest-master.zip 
    [sargandh@CentOS Desktop]$ cd dhtest-master
    [sargandh@CentOS dhtest-master]$ make
    gcc    -c -o dhtest.o dhtest.c
    gcc    -c -o functions.o functions.c
    gcc dhtest.o functions.o -o dhtest
    [sargandh@CentOS dhtest-master]$ ls -lh dhtest
    -rwxrwxr-x 1 sargandh sargandh 38K Mar 13 10:47 dhtest

dhtest 1.5 - new 1.5 features supported

* Add option to send DHCP DECLINE packets ('-D' flag)
* Fix potential Segmentation Fault in get_dhinfo() function
* Added dhcp option55 requested parameter list

dhtest 1.4 - till 1.4 features supported

* IP obtaining through DHCP
* Release obtained IP with -r flag
* VLAN
* Broadcast flag support
* DHCP option 50 - Requested IP
* DHCP option 60 - Vendor Class Identifier
* Binding obtained IP for a default timeout of 3600 seconds
* Support of bind timeout with -k flag on command line
* Added DHCP option 51 - Requested lease time from server
* Added DHCP option 12 - Hostname
* Added DHCP option 81 - Fqdn
* Option to send in unicast mode.
* Option to output for nagios.
* Option to change port, patch by Alan Dekok.
* Custom option support - Allows packing of any dhcp option in number/string/hex format

License

Please see the LICENSE file.

Tool usage examples

* https://sargandh.wordpress.com/2012/02/23/linux-dhcp-client-simulation-tool/

* custom option examples
    dhcp option 82 
    --------------
      [root@CentOS dhtest-1.1]# ./dhtest -m 00:00:00:11:11:11 
      -c 82,hex,0108476967302f312f30021130303a30303a30303a31313a31313a3131
                 | ||              |
                 | ||              |Subopt value - 'Gig0/1/0' 
                 | | **************        
                 | Subopt len 8
               Opt82 subopt 1
               Circuit id 

      [root@CentOS dhtest-1.1]# ./dhtest -m 00:00:00:11:11:11 
      -c 82,hex,0108476967302f312f30021130303a30303a30303a31313a31313a3131
                                     | ||              |
                                     | ||              |Subopt value - '00:00:00:11:11:11' 
                                     | | **************        
                                     | Subopt len 17
                                   Opt82 subopt 2
                                   Remote id 

    dhcp option 60 and 82 (multiple custom options) 
    -----------------------------------------------
      [root@CentOS dhtest-1.1]# ./dhtest -m 00:00:00:11:11:11 -c 60,str,"MSFT 5.0" 
      -c 82,hex,0108476967302f312f30021130303a30303a30303a31313a31313a3131 

 * dhcp option55 requested parameter list example

    root@ubuntu-16:~/dhtest# ./dhtest -m 00:00:00:11:11:11 -i enp0s3 -l 011C030F060A0B
    DHCP discover sent       - Client MAC : 00:00:00:11:11:11
    DHCP offer received      - Offered IP : 10.0.2.16
    DHCP request sent        - Client MAC : 00:00:00:11:11:11
    DHCP ack received        - Acquired IP: 10.0.2.16
    root@ubuntu-16:~/dhtest# 

    Tshark output     
    -------------
      Option: (55) Parameter Request List
          Length: 7
          Parameter Request List Item: (1) Subnet Mask
          Parameter Request List Item: (28) Broadcast Address
          Parameter Request List Item: (3) Router
          Parameter Request List Item: (15) Domain Name
          Parameter Request List Item: (6) Domain Name Server
          Parameter Request List Item: (10) Impress Server
          Parameter Request List Item: (11) Resource Location Server