Logging DHCP Packet Information

The JunosE Software enables you to collect and log DHCP packet information for all JunosE DHCP access models on a per-interface basis. To log packets for a specific DHCP application, you enable DHCP packet logging on the interface that serves the application. JunosE Software supports per-interface DHCP packet logging on a maximum of 16 interfaces. Per-interface DHCP packet logging is disabled by default.

You can specify which packets are logged—receive, transmit, or all. You can optionally assign low or high priority to the logged packets. Packets are assigned a low priority by default, which does not interfere with router DHCP packet processing. The logged packets are output to the dhcpCapture event logging category.

You can configure per-interface DHCP packet logging on statically configured and dynamically created IP interfaces. However, configuration information for dynamic interface configurations is lost after a cold restart. Both static and dynamic interface configuration information is maintained after a warm restart.

You use the ip dhcp-capture command with the following keywords to enable DHCP packet logging for all DHCP applications on the interface.

• Use the receive, transmit, and all keywords to specify the type of DHCP packets that is logged.
• Use the optional priority keyword to assign a low or high priority to logged packets. By default, logged packets have a low priority and do not interfere with the router’s DHCP packet processing.

You can specify DHCP packet logging on a maximum of 16 interfaces.

• To enable DHCP packet logging:
  host1(config-if)#ip dhcp-capture all