DHCP configuration on S series switch does not take effect

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DHCP configuration may not take effect on an S series switch due to the following reasons:
1. DHCP server is disabled on the switch.
2. The DHCP address pool is configured incorrectly.
3. No IP network segment is specified on the interface connected to DHCP clients, or the specified IP network segment is on a different network segment from the address pool.
4. If ACL resources are exhausted, the DHCP commands run globally or on an interface will not take effect.

Other related questions:
DHCP configuration does not take effect on the AR
Possible causes are as follows: 1. DHCP is not enabled on the AR. 2. The address pool is configured incorrectly. 3. The IP network segment is not specified on the interface of the DHCP server connected to the client, or the specified IP network segment and address pool are different. 4. If ACL resources are used up, the DHCP command that is run globally or on an interface does not take effect.

IPSG does not take effect on an S series switch. What are the possible causes
If IPSG does not take effect on an S series switch (except the S1700), possible causes include the following: 1. A binding entry is incorrect. a. A static binding table is created using the user-bind static command. If the binding entry of a valid host is not in the binding table, add the host's binding entry to the binding table. If the host's entry exists in the binding table, check whether the MAC address in the entry is the same as the host's MAC address. If the network card of the host is replaced, the MAC address in the entry may not be updated. Check whether the host's entry contains VLAN information. Only when the interface connected to this host has been added to the correct VLAN, the switch allows the packets from the host to pass. b. A dynamic binding table is generated only when DHCP snooping is enabled, the interface connected to the DHCP server is configured as a trusted interface, and then the PC obtains a new IP address. 2. IPSG is not enabled in the specified interface or VLAN view. After a binding table is generated, the IPSG function must be enabled in the interface or VLAN view using the ip source check user-bind enable command. IPSG takes effect only on the interface or VLAN where it is enabled, and IPSG check is not performed on the interfaces or VLANs with IPSG disabled. Therefore, if IPSG does not take effect on an interface or in a VLAN, the IPSG function may not be enabled on this interface or in this VLAN. 3. IPSG is enabled in the VLAN to which the uplink interface belongs. IPSG is enabled on the user-side interface, namely, the downlink interface. If IPSG is enabled on the uplink interface, the packets returned by the gateway may be discarded. As a result, user service is interrupted. Solution: Disable IPSG in the VLAN to which the uplink interface belongs. 4. DHCP snooping is disabled or a DHCP snooping trusted interface is configured on the uplink interface or in the VLAN to which the uplink interface belongs. If DHCP snooping if disabled on an interface using the dhcp snooping disable command, or if a DHCP snooping trusted interface is configured on the interface using the dhcp snooping trusted command, the IPSG function on the interface or in the VLAN to which the interface belongs does not take effect. 5. Hardware ACL resources are insufficient. The hardware ACL resources are used by IPSG and other services. If the ACL resources are insufficient, IPSG cannot take effect. For example, you can run the display dhcp static user-bind all verbose command to view the IPSG status corresponding to static binding entries. If the value of IPSG Status is ineffective, IPSG of this entry does not take effect. The possible cause is that hardware ACL resources are insufficient. 6. A QoS traffic policy conflicts with IPSG. This situation may only occur in V1R6C05. When a QoS traffic policy conflicts with IPSG, the traffic behavior in the QoS traffic policy takes effect. In this situation, you need to modify service configurations.

Why does the egress policy configured on an RR not take effect on S series switches
Q: Why does the egress policy configured on an RR not take effect? A: The route reflection attribute of the reflector is the route attribute determined by the ingress policy and is not affected by either the egress policy or the peer { group-name | ipv4-address | ipv6-address } next-hop-local command.

Mechanism for ACL rules on S series switches to take effect
ACL rules on S series switches are classified into the following two modes: An ACL is bound to the traffic policy and delivered to the hardware of the LPU through the first mode. The second mode relates to software processing. An ACL prevents users from logging in through Telnet. After being sent to the CPU, packets are processed in the sequence that is specified during the configuration of the ACL. Rules in an ACL can be matched according to the depth first principle or the configuration order.

Whether S series switches support IPv6
The IPv6 function of S series modular switches is controlled by a license. By default, the IPv6 function is disabled on a new switch. To use the IPv6 function, apply for and purchase the license from the equipment supplier. - For details about products and versions of the S12700 sereis switches supporting IPv6, see Basic IPv6. - For details about products and versions of the S7700&S9700 sereis switches supporting IPv6, see Basic IPv6. - For details about products and versions of the S9300 sereis switches supporting IPv6, see Basic IPv6. - For details about products and versions of fixed switches supporting IPv6, see Basic IPv6.

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