CustoSec:Check DHCP Device
|Basic Information on Check|
|Name of Check||DHCP Server||Technical Name||check_dhcp_device|
|Available in||All Systems||Number of Arguments||1|
|From Version||ARANSEC 1.0||Compability||All ARANSEC and CustoSec|
Scope of Check
Check to monitor if there is (are) a DHCP Server(s) available and working correctly on the network.
For the check to work properly the following requirements must be met:
- The check has to be configured as a service check for the host, that is working as the DHCP server.
To configure the check, the following arguments are available:
|Argument No.||Argument Name||Allowed Arguments||Explanation||Examples|
|Arg1||Interface||string||Interface of the local host (ARANSEC, CutsoSec) to be used to check for DHCP servers. This interface determines the subnet in which the query will be performed. On an ARANSEC or CustoSec System this would usually be eth1.||!eth1|
Returned Values of the Check
The Check returns the following values and information.
|OK||OK: Received 1 DHCPOFFER(s), 1 of 1 requested servers responded, max lease time = 7200 sec.||The request by the check was answered by the correct server with providing a dhcp lease. Tells us the DHCP Server is working correctly.|
|OK||OK: Received 2 DHCPOFFER(s), 1 of 1 requested servers responded, max lease time = 7200 sec.||The request by the check was answered by the correct server with providing a dhcp lease and another DHCP Server in the network.|
|WARNING||-||WARNING will not be issued|
|CRITICAL||CRITICAL: Received 1 DHCPOFFER(s), 0 of 1 requested servers responded, max lease time = 7200 sec.||This is the response, when there has been a DHCP offer from another server than the one where the service check was targeting. There are two possible reasons for this happening.|
In most cases, the check is configured on the wrong host, thus targeting the wrong host. Since this "wrong" host does not answer with a lease, the request is broadcasted into the network, which leads to another DHCP Server to answer.
The other reason might be, the check is configured correctly but there are other DHCP Server(s) answering the request as well. This is a hint to come problems in the network.
|CRITICAL||CRITICAL: No DHCPOFFERs were received.||This is the checks return, if there was no DHCP Server answering the request. There is no DHCP Server active in this network segment.|