Binding table entries are deleted when a lease expires, or the relay agent encounters a DHCPRELEASE,
DHCPNACK, or DHCPDECLINE.
DHCP snooping is supported on Layer 2 and Layer 3 traffic. DHCP snooping on Layer 2 interfaces does
require a relay agent.
Binding table entries are deleted when a lease expires or when the relay agent encounters a DHCPRELEASE.
Line cards maintain a list of snooped VLANs. When the binding table is exhausted, DHCP packets are dropped
on snooped VLANs, while these packets are forwarded across non-snooped VLANs. Because DHCP packets
are dropped, no new IP address assignments are made. However, DHCPRELEASE and DHCPDECLINE packets
are allowed so that the DHCP snooping table can decrease in size. After the table usage falls below the
maximum limit of 4000 entries, new IP address assignments are allowed.
NOTE:
DHCP server packets are dropped on all not trusted interfaces of a system configured for DHCP
snooping. To prevent these packets from being dropped, configure
ip dhcp snooping trust
on the
server-connected port.
Enabling DHCP Snooping
To enable DHCP snooping, use the following commands.
1
Enable DHCP snooping globally.
CONFIGURATION mode
ip dhcp snooping
2 Specify ports connected to DHCP servers as trusted.
INTERFACE mode
INTERFACE PORT EXTENDER mode
ip dhcp snooping trust
3 Enable DHCP snooping on a VLAN.
CONFIGURATION mode
ip dhcp snooping vlan
name
Enabling IPv6 DHCP Snooping
To enable IPv6 DHCP snooping, use the following commands.
1
Enable IPv6 DHCP snooping globally.
CONFIGURATION mode
ipv6 dhcp snooping
2 Specify ports connected to IPv6 DHCP servers as trusted.
INTERFACE mode
ipv6 dhcp snooping trust
3 Enable IPv6 DHCP snooping on a VLAN or range of VLANs.
CONFIGURATION mode
Dynamic Host Configuration Protocol (DHCP)
359
Содержание S4048T
Страница 1: ...Dell Configuration Guide for the S4048T ON System 9 10 0 1 ...
Страница 98: ... saveenv 7 Reload the system uBoot mode reset Management 98 ...
Страница 113: ...Total CFM Pkts 10303 CCM Pkts 0 LBM Pkts 0 LTM Pkts 3 LBR Pkts 0 LTR Pkts 0 802 1ag 113 ...
Страница 411: ...mode transit no disable Force10 Resilient Ring Protocol FRRP 411 ...
Страница 590: ...Figure 67 Inspecting the LAG Configuration Link Aggregation Control Protocol LACP 590 ...
Страница 591: ...Figure 68 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 591 ...
Страница 594: ...Figure 70 Inspecting a LAG Port on BRAVO Using the show interface Command Link Aggregation Control Protocol LACP 594 ...
Страница 595: ...Figure 71 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 595 ...
Страница 646: ...Figure 87 Configuring Interfaces for MSDP Multicast Source Discovery Protocol MSDP 646 ...
Страница 647: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 647 ...
Страница 648: ...Figure 89 Configuring PIM in Multiple Routing Domains Multicast Source Discovery Protocol MSDP 648 ...
Страница 653: ...Figure 91 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 653 ...
Страница 654: ...Figure 92 MSDP Default Peer Scenario 3 Multicast Source Discovery Protocol MSDP 654 ...
Страница 955: ...Figure 119 Single and Double Tag First byte TPID Match Service Provider Bridging 955 ...
Страница 1179: ...Figure 147 Create Hypervisor Figure 148 Edit Hypervisor Figure 149 Create Transport Connector Virtual Extensible LAN VXLAN 1179 ...