Pradeep Singh | 18th Aug 2017
Dynamic Host Configuration Protocol (DHCP) is a client/server protocol that automatically provides an IP Host with its IP address and other related configuration information such as the subnet mask and default gateway.
udhcpd is the DHCP Server demon which is part of BusyBox and is included by default with core OS (no need to install any additional package). It is a perfect candidate for simple and lightweight DHCP Server. Let’s explore how to create a Tiny Core based DHCP Server –
1. Configure the Ethernet Interface with Static IP Address:
1.1 Create the ethernet config script using the “sudo vi /opt/eth0.sh” command with the following contents (For more details on this you can refer to this Article) –
#!/bin/sh # If you are booting Tiny Core from a very fast storage such as SSD / NVMe Drive and getting # "ifconfig: SIOCSIFADDR: No such Device" or "route: SIOCADDRT: Network is unreachable" # error during system boot, use this sleep statemet, otherwise you can remove it - sleep .2 # kill dhcp client for eth0 sleep 1 if [ -f /var/run/udhcpc.eth0.pid ]; then kill `cat /var/run/udhcpc.eth0.pid` sleep 0.1 fi # configure interface eth0 ifconfig eth0 192.168.10.1 netmask 255.255.255.0 broadcast 192.168.10.255 up # Start the DHCP Server Process once the Interface is Ready with the IP Add sleep .1 sudo udhcpd /etc/udhcpd.conf &
1.2 Assign execute permission to “eth0.sh” script –
sudo chmod 777 /opt/eth0.sh
1.3 Execute the script to configure the “eth0” Ethernet interface using the following command –
sudo /opt/eth0.sh
1.4 Check the Ethernet interface “eth0” –
2. Create “/etc/udhcpd.conf” File:
Create a DHCP Configuration file with the “sudo vi /etc/udhcpd.conf” command and fill it will following template (make the changes according to your DHCP Range requirements) –
start 192.168.10.100 end 192.168.10.200 interface eth0 option subnet 255.255.255.0 option router 192.168.10.1 option lease 43200 option dns 192.168.10.1 option domain local
3. Start DHCP Daemon:
Start the DHCP process using the following command –
sudo udhcpd /etc/udhcpd.conf
Note: In case your DHCP Server is not working try using “-f” option with “udhcpd” command to run it in the foreground and see the error messages on the console. For Example – “sudo udhcpd -f /etc/udhcpd.conf“
4. Verify the DHCP Server Process:
You can use following commands to verify if the DHCP process is running properly using the following commands –
ps -ef | grep udhcpd sudo netstat -anp | grep udhcpd
You should see something like following console output (DHCP Server listens at UDP port 67) –
tc@box:~$ ps -ef | grep udhcpd 913 root udhcpd /etc/udhcpd.conf 933 tc grep udhcpd tc@box:~$ tc@box:~$ sudo netstat -anp | grep udhcpd netstat: /proc/net/tcp6: No such file or directory udp 0 0 0.0.0.0:67 0.0.0.0:* 913/udhcpd netstat: /proc/net/udp6: No such file or directory netstat: /proc/net/raw6: No such file or directory tc@box:~$
4. Make DHCP Server Configuration Persistent:
As Tiny Core runs from system RAM, it would loose the DHCP configuration on system reboot. To make your DHCP configuration persistent use the following commands –
sudo echo '/etc/udhcpd.conf' >> /opt/.filetool.lst
sudo echo '/opt/eth0.sh' >> /opt/.filetool.lst
sudo echo '/opt/eth0.sh &' >> /opt/bootlocal.sh
filetool.sh -b
Following is the console output with sample contents of “.filetool.lst” and “bootlocal.sh” files –
tc@box:~$ sudo echo '/etc/udhcpd.conf' >> /opt/.filetool.lst tc@box:~$ sudo echo '/opt/eth0.sh' >> /opt/.filetool.lst tc@box:~$ tc@box:~$ cat /opt/.filetool.lst opt home /etc/udhcpd.conf /opt/eth0.sh tc@box:~$ tc@box:~$ sudo echo '/opt/eth0.sh &' >> /opt/bootlocal.sh tc@box:~$ tc@box:~$ cat /opt/bootlocal.sh #!/bin/sh # put other system startup commands here /opt/eth0.sh & tc@box:~$ tc@box:~$ filetool.sh -b Backing up files to /mnt/sda1/tce/mydata.tgztc@box:~$ tc@box:~$
5. Reboot the Server:
With this your DHCP Server is ready. You may test the configuration persistence by rebooting the server.
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