ISC DHCP: Quick Configuration with SolarWinds IP Address Manager Share:
What is DHCP? All devices need IP addresses to be able to communicate in a network. DHCP, or Dynamic Host Configuration Protocol, aids in the automatic distribution of IP addresses to devices in the network. A DHCP server replaces the cumbersome and error-prone manual task of allocating IP addresses picked from a spreadsheet or any other document. Illustrated below, is a brief explanation of how a DHCP server services a client device requesting for an IP address. Share: 2
Introduction to ISC DHCP While there are many DHCP services available, Internet Systems Consortium (ISC) is widely used and has been providing BIND DNS and ISC DHCP for over 15 years now. With a market share of over 80%*, the ISC DHCP solution operates at high performance, is reliable, and supports both IPv4 and IPv6 addresses. It s open source software that implements DHCP to connect to an IP network and is suitable for both small local networks and large enterprises. ISC DHCP is available as a free download under the terms of the ISC License. Installing ISC DHCP Steps to install ISC DHCP service on Linux : 1. To install the service, use the get command at the terminal prompt as shown below. sudo apt-get install isc-dhcp-server On KUBUNTU or UBUNTU Linux distribution 2. Then, configure the ISC service so that it operates with the default settings. 3. Assign a static IP to the interface that is used for DHCP, the default interface is eth0. If eth0 is providing addresses from subnet 192.168.100.0/24, then the static IP assigned will be 192.168.100.1. You also need to specify all the interfaces that you want the DHCP server to listen to. To assign a static IP and specify interfaces, edit the file the location shown below. /etc/default/isc-dhcp-server To assign a static IP, edit the file at this location 4. Finally, restart the DHCP to complete the initial configuration. service isc-dhcp-server restart Restart the service on the server Share: 3
Creating Subnets and IP Reservations Once the initial configuration is complete, configure subnets and options using the below mentioned commands. nano -w /etc/dhcp3/dhcpd.conf Specified subnet properties will lease an IP for 600 seconds or for a max. of 7200 seconds default-lease-time 600; max-lease-time 7200; option subnet-mask 255.255.255.0; option broadcast-address 192.168.1.255; Router/Gateway option routers 192.168.1.254; option domain-name-servers 192.168.1.1, 192.168.1.2; option domain-name "mydomain.example"; subnet 192.168.1.0 netmask 255.255.255.0 { range 192.168.1.10 192.168.1.100; range 192.168.1.150 192.168.1.200; sudo service isc-dhcp-server-restart Subnet mask that the client should use Broadcast address that the client should use DHCP server will assign clients an IP address from this range DNS Servers Share: 4
Configuring ISC DHCP To specify a WINS server for your Windows clients, you ll need to include the netbios-name-servers. A sample configuration of subnets may look like this and the same can be used to configure multiple interfaces as well. nano -w /etc/dhcp3/dhcpd.conf ddns-update-style none; log-facility local7; subnet 192.168.1.0 netmask 255.255.255.0 { option routers 192.168.1.1; option subnet-mask 255.255.255.0; option broadcast-address 192.168.1.255; option domain-name-servers 194.168.4.100; option ntp-servers 192.168.1.1; option netbios-name-servers 192.168.1.1; option netbios-node-type 2; default-lease-time 86400; max-lease-time 86400; Reservation/Host name MAC Address host bla1 { hardware ethernet DD:GH:DF:E5:F7:D7; fixed-address 192.168.1.2; host bla2 { hardware ethernet 00:JJ:YU:38:AC:45; fixed-address 192.168.1.20; subnet 10.152.187.0 netmask 255.255.255.0 { IP Address option routers 10.152.187.1; option subnet-mask 255.255.255.0; option broadcast-address 10.152.187.255; option domain-name-servers 194.168.4.100; option ntp-servers 10.152.187.1; option netbios-name-servers 10.152.187.1; option netbios-node-type 2; Share: 5
default-lease-time 86400; max-lease-time 86400; host bla3 { hardware ethernet 00:KK:HD:66:55:9B; fixed-address 10.152.187.2; Configuration files in ISC DHCP are in plain text and run into many lines of code. Editing a subnet involves scanning the entire file, which can turn out be very time consuming. Making the smallest change involves using CLI (Command Line Interface) and hence the need for skilled resources adept with CLI commands. The absence of monitoring mechanisms to detect full subnets makes it difficult to find details on subnet utilization and available IP addresses. These management hassles can be simplified and overcome with tools like SolarWinds IP Address Manager (IPAM). SolarWinds IPAM offers a user-friendly interface through which administrators can easily: Create/modify subnets. Create/modify IP ranges. Specify pools, IP ranges, and leases. The administrative benefits of using SolarWinds IPAM are: Reduce manual editing of complex and error-prone plain-text configuration files. Obtain consolidated reports on IP usage and scope utilization to aid in accurate provisioning of your IP space. Receive alerts whenever subnets are nearing full capacity or when there is an IP conflict in the network. Increased security by providing credentials to log on to the DHCP server to make changes. Share: 6
To configure ISC DHCP and manage your DHCP with SolarWinds IPAM, first install ISC as mentioned in the Installing ISC DHCP section. Once done, select the DHCP server where you want to create a new subnet and click "Add DHCP Scope". ISC DHCP with SolarWinds IPAM SolarWinds IPAM simplifies creation and edition of ISC subnets to a few clicks. This means you ll no longer need to log on to CLI every time you need to make a change! Click to Add new subnet With SolarWinds IPAM s simple wizard, you can create/modify subnets and specify scope properties like exclusions, pools, IP ranges, and leases without having to manually edit remote configuration files. Share: 7
The Edit DHCP Scope Wizard guides you through the process of modifying existing DHCP properties. You can define/edit scope properties by providing server details, scope name, description, location, etc. Specify the required IP address ranges and pools. Specify IP ranges & pools for IP addresses Share: 8
Specify the lease time for which an IP address must be allocated to a client. If the client requests for a particular lease time, then IPAM will meet the requirement up to the maximum value mentioned in Maximum Lease Time field. Easily set required DHCP configuration options through SolarWinds IPAM. Simply choose from a drop down and specify required values for the desired option. SolarWinds IPAM provides support for almost all options specified in RFC2132. To configure an option, click on Add New Options and choose the required option from a drop down list of available DHCP options. Click on Update Scope to create scope and update changes on the DHCP server Share: 9
For example, to configure option 066 (specifies the server name to identify the TFTP server used for DHCP options), just select 066-Server Name from the list and give the IP address of the server in the Value field. Then click Save. Finally, Review scope details and click on Update scope. The scope created/modified automatically gets updated on the server. Share: 10
Key Benefits of Using SolarWinds IPAM for ISC DHCP Reduce use of complex and error-prone Command Line Interface (CLI) and manage your ISC DHCP & BIND DNS server from a user friendly GUI. Propagate all DHCP & DNS changes made via SolarWinds IPAM to the ISC DHCP & BIND server with the click of a button. Single management console to monitor & manage your Microsoft, Cisco and ISC DHCP as well as Microsoft and BIND DNS servers. Active monitoring and preventive alerting when a subnet nears full utilization or there are IP conflicts in the network. Reference: Internet System Consortium: https://www.isc.org/downloads/dhcp/ https://www.isc.org/blogs/whats-your-version/ Ubuntu Documentation: https://help.ubuntu.com/community/isc-dhcp-server Share: 11
SolarWinds IPAM seamlessly integrates into your existing DHCP and DNS environment with quick and easy deployment in as little as an hour. Summary View in SolarWinds IPAM Share: 12
SolarWinds (NYSE: SWI) provides powerful and affordable IT management software to customers worldwide - from Fortune 500 enterprises to small businesses. The company works to put its users first and remove the obstacles that have become status quo in traditional enterprise software. SolarWinds products are downloadable, easy to use and maintain, and provide the power, scale, and flexibility needed to address users management priorities. SolarWinds online user community, http://thwack.com, is a gathering-place where tens of thousands of IT pros solve problems, share technology, and participate in product development for all of the company s products. Learn more today at http://solarwinds.com. For additional information, please contact SolarWinds at 866.530.8100 or e-mail sales@solarwinds.com. To locate an international reseller near you, visit http://www.solarwinds.com/partners/reseller_locator.aspx Share: 13