Week 7 Blog

Dynamic Host Configuration

Dynamic Host Configuration Protocol

Linux can both use dynamic host configuration protocol (DHCP) to get network information and be used to act as a DHCP server. These types of servers can grab addresses from a pool when it’s requested. Additionally, Locations of DNS servers and default internet gateways are distributed. Now get ready for the borderline confusing setting and configuration for a DHCP server.

Manual IP Configuration

There’s four fields that need to be set after the network configuration tool is launched. These four are:

·         IP address – This can be left alone or be set manually. A static IP address of machines has an IP address that does not change even after reboot.

·         Subnet mask – The subnet mask is responsible for getting the range of addresses for the computers and devices on the LAN or subnet.

·         Default gateway – Whenever the need to leave your LAN, the request needs to figure out what node on the subnetwork will route to outside the LAN. The gateway can route the requests for IP addresses that are outside of the local subnet.

·         Domain name system (DNS) – It’s hard for people to remember IP address in full so we give them host names. The DNS translates this so when we do something with a host name the system sees it as an IP address.

Configuring a DHCP Client

There’s four important network parameters that need to be set when setting up a DHCP server. Lease time is a time set for clients for how long they can use the IP address from the DHCP server. This lease can be renewed if the client makes a request. Without any configuration, the lease time is set at 86,400 seconds, which is 24 hours. Host workstations can be assigned a name with the use of DHCP as well. The configuration file is found under /etc/dhcp/dhclient.conf. Typically, the DHCP client configuration file doesn’t need to be touched, but it’s good to know how everything works, specially setting the parameters.

Configuring a DHCP Server

Installing the DHCP package is the first step to setting up a DHCP server. Next is making sure that the firewall is allowing communication through the two UDP ports 67 & 68. The next is opening and editing the configuration file found under /etc/dhcp/dhcpd.conf. Once your parameters are set it’s time to launch the dhcpd server daemon. The next two steps are to set up the host firewall, and then the DHCP configuration file under /etc/dhcp/dhcpd.conf. After your parameters are set you are done (after testing of course).