32.9. Adding and Editing Groups
Unlike subnets, hosts, and shared networks, group entries in the DHCP server configuration do not actually effect the server's behavior in any way. Instead, they are just used to define options that will apply to multiple hosts. Even though there are other ways that this can be achieved (such as putting the hosts under a subnet), using a group gives you extra flexibility.
Groups can be defined under subnets and shared networks, but not other groups. Groups do not normally have names. Instead, they are identified in Webmin by the number of hosts that they contain. Newer versions of the DHCP server do support group names and Webmin will display them, but there is no support yet in the module for setting the name of a group.
To create a new host group, follow these steps:
1. | On the module's main page, click on the Add a new host group link under Hosts and Host Groups to go to the group creation form. |
2. | Select any existing hosts that you want to be members of this group from the Hosts in this group list. |
3. | If you want this group to be under a subnet, choose Subnet from the menu in the Group assigned to field and select the subnet in the list next to it. All hosts in the group must have fixed IP addresses that fall within the subnet's network. Similarly, a group can be created inside a shared network by choosing Shared Network from the menu and selecting the network name from the list. In both cases, the group will inherit client options and other settings (like the lease length) from its parent subnet or shared net. |
4. | If hosts in the group need to network boot from a server, enter the name of that server into the Boot file server field. You must also fill in the Boot filename field with the path to an appropriate boot file (downloadable via TFTP) on the boot server. |
5. | Click the Create button. You will be returned to the module's main page, which will now include an icon for the new group. |
6. | Click on the group icon to bring up its editing form, and then on Edit Client Options. This will take you to the page shown in Figure 32.4 for setting options that are sent to client hosts in this group. |
7. | Set any of the options such as the DNS or NIS servers by following Steps 10 through 18 of Section 32.4 “Adding and Editing Subnets”. |
8. | Click the Save button at the bottom of the page to save the options and return to the group form. |
9. | Go back to the module's main page and hit Apply Changes to make your new group active. |
Once a group has been created, new or existing hosts can be moved into it using the Host assigned to field on the host form. Any host added to a group will inherit client options and network boot settings from the group, unless overridden by settings for the host itself.
As usual, a group can be edited by clicking on its icon on the module's main page, making changes, and clicking Save. A group can also be removed with the Delete button on its editing page. However, if it contains any hosts, you will be asked to confirm the deletion before it and the hosts are actually removed.
A group can also be created under a subnet or shared network by clicking on the Add a new host group link on the page reached by clicking on one of their icons. The group creation form that is displayed no longer has a Group assigned to field. Instead, the name of the subnet or shared network to which it will be added is displayed at the top of the page. Apart from that difference, the preceding instructions can still be followed.