Display IP addresses of clients connected to S series switch

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When an S series switch, except S1700, works at Layer 2, only the MAC address of the interface is displayed, but IP address is not displayed.
When an S series switch, except S1700, works at Layer 3 and you have known the MAC address of a connected client, you can run the display arp all command to check the IP address of the client. If you do not know the MAC address of the client, run the ipconfig/all command on your PC.
For example:
display arp all

IP ADDRESSMAC ADDRESSEXPIRE(M) TYPEINTERFACEVPN-INSTANCE
VLAN/CEVLAN

10.137.217.202 00e0-0987-7890 I - Eth0/0/0
10.137.216.1 0000-5e00-0149 20 D-0 Eth0/0/0

Total:2 Dynamic:1 Static:0 Interface:1
(1) The IP address of the PC with MAC address 00e0-0987-7890 is 10.137.217.202.
(2) The total number of dynamic and static ARP entries is the number of access users.

Other related questions:
Can clients connected to S series switch obtain IP addresses through DHCP
DHCP-enabled terminals that are connected to S series switches except S1700 switches can obtain IP addresses from DHCP servers when either of the following conditions is met: - The DHCP server function has been enabled on the switches. (By default, the DHCP server function is disabled on a switch.) - A DHCP server is available on the network and reachable to the terminals.

View VLANs mapped to IP addresses of clients connected to S series switches
On S series switches, you can view ARP entries to obtain the VLANs mapped to the IP addresses of clients connected to the switches. The following is an example: [HUAWEI] display arp all IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPN-INSTANCE VLAN/CEVLAN ---------------------------------------------------------------------------------------------------------------------------- 10.133.217.202 00e0-0987-7890 I - Eth0/0/0 10.133.216.1 0000-5e00-0149 20 D-0 Eth0/0/0 10.1.1.2 00e0-0987-7899 I - GE6/1/1 192.168.11.254 aaaa-bbbb-cc92 12 D-0 Eth-Trunk1 11/- 192.168.11.253 ac85-3da6-a420 16 D-0 Eth-Trunk1 11/- ---------------------------------------------------------------------------------------------------------------------------- Total:5 Dynamic:3 Static:0 Interface:2 The two clients with the IP addresses 192.168.11.254 and 192.168.11.253 belong to VLAN 11.

DHCP clients on S series switch cannot detect IP address conflicts
Before a DHCP client binds an obtained IP address to a VLANIF interface, it proactively sends a gratuitous ARP packet to check for IP address conflict. The VLANIF interface does not have an IP address, so its protocol status cannot go Up. When the physical interface in the corresponding VLAN receives the gratuitous ARP packet with the conflicting IP address, it cannot send the packet to the CPU. As a result, the DHCP client cannot detect IP address conflict. To resolve this problem, configure the dhcp server ping function on the DHCP server to check for IP address conflict. When there is a large number of DHCP clients, this function requires a high cost, so you need to decide whether to use this function after thorough consideration.

Why different clients obtain the same IP address
When an S series switch functions as a DHCP server, a DHCP client accesses the network again in the following process: The DHCP client broadcasts a DHCP Request packet carrying the IP address allocated in the first time, that is, the Option 50 field in the packet. After receiving the DHCP Request packet, the DHCP server checks whether the lease record exists based on the MAC address in the packet. If so, the DHCP server replies with a DHCP ACK packet to notify the DHCP client that the requested IP address can be used. If not, the DHCP server waits for a new DHCP Discover message from the client.

The leases of some addresses are displayed as - on S series switch
When the display ip pool [ { interface interface-pool-name | name ip-pool-name } [ start-ip-address [ end-ip-address ] | all | conflict | expired | used ] ] command is executed on an S series switch (except an S1700 switch) to display information about IP addresses in a DHCP address pool, the Lease field in the command output is displayed as hyphens (-) for idle, excluded, statically bound, and conflicting IP addresses.

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