S series switches how to locate the downlink AP can not get the IP address


For S series switches (except S1700):
In an networking such as AC-S5700-AP, the AC assigns an IP address to the AP through the DHCP method. If the AP does not obtain an IP address, the checks on the switch are as follows:
- Run the display arp command to check whether the MAC address of the connected AC and AP is learned on the switch.
- Run the display dhcp snooping configuration command to check whether DHCP snooping is configured on the switch and the DHCP packets received by the switch connected to the AC and AP are filtered out.
If there is no problem with the checks made above, check the configuration on the AC and AP.

Other related questions:
How can I check whether a loop exists on an S series switch
The simplest way to check the existence of a loop on an S series switch (except the S1700) is to check whether a MAC address flapping alarm exists on the switch. If the alarm exists, you can quickly locate the loop based on the information in the alarm. Run the display mac-address flapping record command to check whether MAC address flapping exists, or run the display trapbuffer command to check whether the alarm contains The mac-address has flap value or MAC move detected. For more information, visit Layer 2 Loop Troubleshooting.

Can a switch allocate IP addresses to APs
A DHCP server can allocate IP addresses to APs if the DHCP server supports Option 43. Any device can function as a DHCP server if APs can obtain their IP addresses and the AC' IP address from the device in Layer 3 networking. Ensure that APs can ping the AC' source IP address.

How do APs obtain the AC IP address
You can manually configure the AC IP address for APs. APs can also obtain the AC IP address from Layer 2 CAPWAP broadcast packets, Option 43 in Layer 3 packets, or DNS server.

Recommended method for APs to obtain the AC IP address
The DHCP Option 43 method is recommended. This method is not restricted by Layer 2 networking. It is easy to implement and requires no modification or deployment of a DNS server.

How to get the IP address of IAD device
You can query the IAD address of the IP in two ways: Method one: in connection to the IAD on the phone call *127 to listen to the voice broadcast IP address. Method two: view through the serial port 1 maintenance terminal (PC) serial port and IAD port through the standard RS232 serial port connected to the IAD interface through the serial port CONSOLE. 2 execute the display IPAddress command in the normal user mode to view device address information. Commands are as follows: TERMINAL>display ipaddress -------------------------------------------------- DNS Domain Name...............: Physical Address..............: 00-e0-fc-08-ff-af /*MAC address*/ IP Address Get Method.........: Static IP config /*the way to get IP address*/ cpm (unit number 0): Flags: (0x68043) UP BROADCAST MULTICAST ARP RUNNING IP Address..................: Subnet Mask.................: Default Gateway.............: --------------------------------------------------

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