DHCP Forwarder Application
Published: December 21, 2012
This chapter describes how to install the DHCP forwarder application as well as adding and removing resources.
Note This module is relevant only when the DHCP Lease Query Login Event Generator (LEG) or the DHCPv6 Lease Query LEG is installed on the Cisco Service Control Subscriber Manager server. See the "DHCP Forwarder Application Enhancements for DHCPv6" chapter.
The DHCP Forwarder application acts as a bridge between the DHCP Lease Query LEG and the DHCP servers. The LEG sends a request to the DHCP Forwarder, which then forwards the request to the appropriate DHCP server. The DHCP Forwarder passes the replies from the DHCP servers to the LEG. The LEG signals the forwarder which server should receive each request. Therefore, no special configuration is needed for this application.
The DHCP Forwarder runs with root privileges; because only those applications that have root privileges can open ports below 1024. DHCP uses ports 67 and 68. No other application must use these ports.
•Installing the DHCP Forwarder
•Uninstalling the DHCP Forwarder
•DHCP Forwarder Veritas Cluster Server Agent
Installing the DHCP Forwarder
Step 1 Run the DHCP Forwarder installation script from the SM DIST root directory.
Run the installation script as root.
The installation script extracts DHCP Forwarder distribution to the sm-inst-dir \sm\server\addons\dhcp-forwarder directory (sm-inst-dir refers to the Subscriber Manager installation directory). The script adds the initialization scripts to their location according to the operating system running on the machine.
Step 2 (Optional) Confirm that the following ports are not being used by any other application:
Step 3 Run the DHCP Forwarder application.
This application can be run using one of the following methods:
•Restart the machine. The initialization script will start the application automatically.
•Run the following command as root:
Note It is not possible to run the install-forwarder.sh script if the /etc/motd file exists. The file should be moved or removed prior to running the script. Use the ps -eaf | grep DHCP command to view the running process of the DHCP Forwarder.
Uninstalling the DHCP Forwarder
Step 1 Stop the DHCP Forwarder application.
Run the following command as root to stop the application.
Step 2 Remove the DHCP Forwarder application startup and shutdown scripts.
Run the following command as root to remove the startup and shutdown scripts.
# rm /etc/rc*.d/[SK]*p3dhcpforwarder
# rm /etc/init.d/p3dhcpforwarder
•For Red Hat:
# rm /etc/rc.d/rc*.d/[SK]*p3dhcpforwarder
# rm /etc/rc.d/init.d/p3dhcpforwarder
Step 3 Remove the DHCP Forwarder application directory.
Run the following command to remove the application.
# rm -r ~pcube/sm/server/addons/dhcp-forwarder
DHCP Forwarder Veritas Cluster Server Agent
To verify that the DHCP Forwarder process is active at all times, a Veritas Cluster Server (VCS) Agent of type OnOnlyProcess is added as a resource.
•Adding a DHCP Forwarder Resource
•Removing a DHCP Forwarder Resource
Adding a DHCP Forwarder Resource
Step 1 Import the OnOnlyProcess agent's type from the /opt/VRTSvcs/bin/OnOnlyProcess/OnOnlyProcess.cf file.
Step 2 Add an OnOnlyProcess resource called DHCP_Forwarder to the service group.
Step 3 Note the path and arguments of the DHCP Forwarder.
Run the following command via a Telnet session on each of the servers:
Look for the line containing the text "DHCP_FORWARDER". This line contains the path and arguments of the DHCP Forwarder to be used in the next step.
Step 4 Define the OnlineCmd, PathName, and Arguments parameters.
Define the parameters as follows:
•OnlineCmd—Type the DHCP Forwarder start command:
•PathName—Type the DHCP Forwarder process path (from the previous step). For example: /opt/pcube/j2re1.4.2_05/bin/java
•Arguments—Type the DHCP Forwarder process arguments (from the previous step). For example: DAPP=DHCP_FORWARDER -jar /opt/pcube/sm/server.
For further information about the parameters, see Figure 10-1.
Figure 10-1 Adding a DHCP Forwarder Resource
Note The arguments line might seem shorter than the actual full argument list. This is perfectly acceptable.
Removing a DHCP Forwarder Resource
Step 1 Right-click on the DHCP Forwarder Resource icon and choose Delete from the drop-down menu (Figure 10-2).
Figure 10-2 Removing a DHCP Forwarder Resource