Symptoms:
Facts:
Causes:
AP2750 DAPs generate a DHCP request every second. Prior to issuing the DHCP offer, the Router 5012 issues an ICMP Echo to confirm if the IP address assigned is currently assigned to another client. Because of the delay in issuing the DHCP offer pending the ICMP ECHO response and the receipt of the next DHCP request from the same DAP, the DHCP Offer is not issued by the Router 5012.
Fixes:
Pending a solution in the AP2750 boot firmware, use one or the other possible router configurations discussed below.
The Router 5012 will issue an ICMP Echo ( ping) prior to issuing a DHCP Offer. The intent of the ICMP Echo is to determine if there is currently a device in the network with that potential IP address already assigned. The command to disable the ICMP Echo is:
[5012 # ]dhcp server ping ? packets Define number of ping packets timeout Define ping timeout [5012 # ]dhcp server ping packet ? INTEGER<0-10> Number of ping packets (0 to disable pings) [5012 # ]dhcp server ping packet 0
NOTE: The risk at disabling the PING is that there may be a device that has that IP address statically defined or had been assigned at one time by another DHCP server and its lease not aged out. This introduces the possibility of a duplicate IP address being assigned.
An alternative method is to create a static mapping of an IP address from the DHCP pool to a specific DAP's MAC address. As an example, see the configuration that creates a unique IP address pool and assigns an IP address to a specific DAP MAC address:
# dhcp server ip-pool c2_35_c0_200 static-bind ip-address 129.213.124.200 mask 255.255.252.0 static-bind mac-address 000f-cbc2-35c0 gateway-list 129.213.124.1 #
— David Gonzalez 2021/03/31 12:53