
Chapter 9
| General Security Measures
DHCPv6 Snooping
– 322 –
wall. When DHCPv6 snooping is enabled globally by this command, and
enabled on a VLAN interface by the
command, DHCP
messages received on an untrusted interface (as specified by the
no ipv6 dhcp
command) from a device not listed in the DHCPv6 snooping
table will be dropped.
◆
When enabled, DHCPv6 messages entering an untrusted interface are filtered
based upon dynamic entries learned via DHCPv6 snooping.
◆
Table entries are only learned for trusted interfaces. Each entry includes a MAC
address, IPv6 address, lease time, binding type, VLAN identifier, and port
identifier.
◆
When DHCPv6 snooping is enabled, the rate limit for the number of DHCPv6
messages that can be processed by the switch is 100 packets per second. Any
DHCPv6 packets in excess of this limit are dropped.
◆
Filtering rules are implemented as follows:
■
If global DHCPv6 snooping is disabled, all DHCPv6 packets are forwarded.
■
If DHCPv6 snooping is enabled globally, and also enabled on the VLAN
where the DHCPv6 packet is received, DHCPv6 packets are forwarded for a
trusted
port as described below.
■
If DHCPv6 snooping is enabled globally, and also enabled on the VLAN
where the DHCP packet is received, but the port is
not trusted
, DHCP
packets are processed according to message type as follows:
DHCP Client Packet
■
Request: Update entry in binding cache, recording client’s DHCPv6
Unique Identifier (DUID), server’s DUID, Identity Association (IA) type, IA
Identifier, and address (4 message exchanges to get IPv6 address), and
forward to trusted port.
■
Solicit: Add new entry in binding cache, recording client’s DUID, IA type,
IA ID (2 message exchanges to get IPv6 address with rapid commit
option, otherwise 4 message exchanges), and forward to trusted port.
■
Decline: If no matching entry is found in binding cache, drop this
packet.
■
Renew, Rebind, Release, Confirm: If no matching entry is found in
binding cache, drop this packet.
■
If the DHCPv6 packet is not a recognizable type, it is dropped.
If a DHCPv6 packet from a client passes the filtering criteria above, it will
only be forwarded to trusted ports in the same VLAN.
Содержание ECS4120-28F
Страница 36: ...Contents 36...
Страница 38: ...Figures 38...
Страница 46: ...Section I Getting Started 46...
Страница 70: ...Chapter 1 Initial Switch Configuration Setting the System Clock 70...
Страница 86: ...Chapter 2 Using the Command Line Interface CLI Command Groups 86...
Страница 202: ...Chapter 5 SNMP Commands Additional Trap Commands 202...
Страница 210: ...Chapter 6 Remote Monitoring Commands 210...
Страница 216: ...Chapter 7 Flow Sampling Commands 216...
Страница 278: ...Chapter 8 Authentication Commands PPPoE Intermediate Agent 278...
Страница 360: ...Chapter 9 General Security Measures Port based Traffic Segmentation 360...
Страница 384: ...Chapter 10 Access Control Lists ACL Information 384...
Страница 424: ...Chapter 11 Interface Commands Power Savings 424...
Страница 446: ...Chapter 13 Power over Ethernet Commands 446...
Страница 456: ...Chapter 14 Port Mirroring Commands RSPAN Mirroring Commands 456...
Страница 488: ...Chapter 17 UniDirectional Link Detection Commands 488...
Страница 494: ...Chapter 18 Address Table Commands 494...
Страница 554: ...Chapter 20 ERPS Commands 554...
Страница 620: ...Chapter 22 Class of Service Commands Priority Commands Layer 3 and 4 620...
Страница 638: ...Chapter 23 Quality of Service Commands 638...
Страница 772: ...Chapter 25 LLDP Commands 772...
Страница 814: ...Chapter 26 CFM Commands Delay Measure Operations 814...
Страница 826: ...Chapter 27 OAM Commands 826 1 1 00 12 CF 6A 07 F6 000084 Enabled Disabled Enabled Disabled Console...
Страница 836: ...Chapter 28 Domain Name Service Commands 836...
Страница 848: ...Chapter 29 DHCP Commands DHCP Relay Option 82 848...
Страница 902: ...Section III Appendices 902...
Страница 916: ...Glossary 916...
Страница 926: ...CLI Commands 926...
Страница 937: ......
Страница 938: ...E092017 CS R02...