Dell PowerConnect 5548 User Guide - Page 566

As shown in Table 21-1, the DHCP Snooping Binding database is updated by interception of DHCPACK, DHCPDECLINE and DHCPRELEASE packets, and is stored in non-volatile memory. Even if a port is down, its entries are not deleted. NOTE: Only DHCP requests on untrusted ports are maintained in the Binding database. Limitations The following limitations apply: • Enabling DHCP snooping uses TCAM resources. • The switch writes changes to the binding database only when the switch system clock is synchronized with SNTP. • The switch does not update the Binding database when a station moves to another interface. Global Parameters Use the Global Parameters page to: • Enable/disable DHCP snooping globally. • Determine whether to forward or filter DHCP packets received from untrusted interfaces, whose source MAC address and the DHCP client MAC address do not match. • Determine whether to forward or filter DHCP packets, received from untrusted interfaces, with option-82 information. • Set Binding database update interval. 566 Dell PowerConnect 55xx Systems User Guide