Linux DHCP

Splunk for Linux DHCP provides "operational intelligence" and "situational awareness" by establishing baselines and alerting on deviations, delivering supplemental data to add context and correlation, and providing a real-time view into your network infrastructure.

Release Notes

Features

Four Dashboards:

  • Trends shows four panels with operational overviews of your dhcpd trends, including top and rare MAC address vendors
  • Templates allows you to search your dhcpd data without getting in to the complexities of the Splunk search language
  • Trends (RT) shows the same basic visualizations as the above Trends dashboard but updates in real time
  • Transactions (RT) shows dhcpd transactions grouped together by IP address

MAC Prefix-to-Vendor Mapping

  • Splunk for DHCPD uses a static lookup built from IEEE information to automatically map MAC address prefixes to MAC address vendors

14 Saved Searches

  • Splunk for DHCPD comes with fourteen saved searches that power dashboards, alerts, reports, and real-time trends.

26 Event Types

  • Splunk for DHCPD comes with twenty-six event types that help you understand what each dhcp event means and powers several visualizations

Base-lining and Anomaly Detection

  • Splunk for DHCPD compiles a lookup of all known MAC address, IP address, and MAC vendor combinations to form a baseline for your network, and will email you every time a previously unseen host appears on the network.

CEF-Ready

  • Splunk for DHCPD ships with all the plumbing required to output CEF-formatted events in combination with our forthcoming real-time routing framework

Getting Started

To get started with the Splunk for DHCPD, please perform the following configuration:

Permissions

By default, permissions are set at the app level - users in the 'admin' role have read and write permissions, while users in the 'dhcpd' role have read-only permissions.

You can change the app level permissions by navigating to Manager >> Apps >> dhcp "Permissions". Use caution!

Field Extractions

To ensure that field extractions are working properly, you will need to ensure that the correct source type is linked to the field extractions and lookups.

By default, the app will already work if your dhcpd events are coming in under the source types "syslog" or "dhcpd".

Otherwise, you should copy $SPLUNK_HOME/etc/apps/dhcpd/default/props.conf to $SPLUNK_HOME/etc/apps/dhcpd/local/props.conf, and change one of the existing stanzas ([dhcpd] or [syslog]) to the source type that your dhcpd data is in while deleting the other props.conf stanza.

For example, to set the field extractions and lookups to work with the source type foobar, $SPLUNK_HOME/etc/apps/dhcpd/local/props.conf should look as follows:

[foobar]
TRANSFORMS-dhcpd=set-dhcpd-sourcetype
REPORT-dhcpd=dhcpack_type1,dhcpack_type2,dhcpnak,dhcprequest,dhcpdiscover,dhcpoffer,dhcpinform,dhcprelease,dhcp_forward_map_failed,dhcp_added_reverse_map,dhcp_added_forward_map,dhcp_removed_reverse_map,dhcp_leases,dhcp_decls,dhcp_deleted_decls,dhcp_dyn_plus_stat_line1,dhcp_dyn_plus_stat_line2,dhcp_dyn_plus_stat_line3,dhcp_rrset_no_exists,dhcp_rrset_exists,dhcp_duplicate,dhcp_abandon_ip,dhcp_icmp_reply_lease_valid,dhcp_xing_on,src_mac_prefix
LOOKUP-dhcpd=dhcpd_mac-vendorname src_mac_prefix OUTPUT src_mac_vendor
LOOKUP-dhcpd=dhcpd_cef-lookup eventtype OUTPUT cef_version cef_dvendor cef_dproduct cef_dversion cef_sid cef_name cef_severity

Saved Searches

Most of the saved searches and dashboards depend on the event type "dhcpd_event" being defined correctly. By default, this event type is defined as "process=dhcpd", so if you have performed the initial step of getting the field extractions to work, you should be all set. If you still have problems, please post to answers.splunk.com using the link on this page.

Alerts

The alert "dhcpd_alert_new_mac_address_15m" will email you when a new host shows up on your network. The results contained in this alert will be fairly verbose the first few times that it runs, as it takes a while for a baseline to be established, so you might want to consider disabling the action to send you an email for a day or two.

In any case, you will want to change the "Email address(es)" from "example@example.com" to your desired email address or distribution list.

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Built by Alex Raitz