Verified that the MAC-address of the client that cannot obtain an IP address is learnt on switch A<?xml:namespace prefix = "o" />
[R6_U24_S5710_Stack]display mac-address
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MAC Address VLAN/VSI Learned-From Type
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643e-8c43-2a7f 200/- GE0/0/2 dynamic
28d2-443c-0c2c 300/- GE0/0/2 dynamic
-Collected a packet capture on the switch by using the port mirroring command to verify if the DHCP request sent by the client is received and sent by it.
According to the packet capture we can observe that the switch receives the DHCP request from the client but does not forward them further even though between the client and the server we have L2 connectivity. Given the packet capture, we can conclude that the packets are dropped by the switch.
Root Cause
Solution
To solve the problem we enabled the DHCP function on the switch by running the “dhcp enable “command in order to have the received DHCP packets processed and forwarded by the CPU of the switch.
After further investigation we noticed, that the problem in question appears in the vlans that do not have the dhcp function enabled in the situation where the switch is configured as a DHCP client in an interface with the “ip address dhcp alloc-ip" command without having the DHCP function globally enabled globally.
