Are you trying to fix 'isc-dhcp-server: Job failed to start' error?

This guide is for you.

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to resolve DHCP related errors.

In this context, you will see how to fix the error 'isc-dhcp-server Job failed to start'.

How to fix 'isc-dhcp-server: Job failed to start' error ?

Recently, we had a customer who has eth0 and eth1. His eth0 has dynamic IP-address and eth1 has static IP-address. 

After installing isc-dhcp-server, he went to this one /etc/dhcpd.conf with the following command:

default-lease-time 650;
max-lease-time 79520;
option subnet-mask 255.0.0.0;
option broadcast-address 10.10.0.255;
option routers 10.10.0.2;
subnet 10.10.0.0 netmask 255.0.0.0
{
range 10.10.0.10 10.10.0.250;
}

Then he tried to start the server by running the below command:

sudo /etc/init.d/isc-dhcp-server start

As a result, he received the below error message:

start: Job failed to start

Now let's take a look at the solution our Support Experts provide to resolve this error.

Here, we found that the customer was using 8 bit subnet mask.

So it is not possible to use 10.10.0.0 with 8 bit subnet mask. 

So we suggested either to change it to 10.0.0.0 or change the mask to 255.255.0.0.

Finally, it must be as below:

subnet 10.0.0.0 netmask 255.0.0.0

We can also run the DHCP daemon directly to get more information because the startup scripts will eat the error messages:

sudo /usr/sbin/dhcpd -df

This will display the specific complaints it has with the configuration file.

Also, we can see the manual page for the details of -d and -f:

$ man dhcpd

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