A network engineer is deploying new point-of-sale (POS) terminals on VLAN 105 (). The enterprise central DHCP server resides on VLAN 10 (). During initial testing, the POS terminals fail to obtain leased IP addresses and continuously self-assign IP addresses in the range of through . Which of the following potential root causes or diagnostic actions should the engineer investigate to resolve this connectivity issue? (Select TWO.)
- Verify whether an IP helper address pointing to is configured on the Layer 3 interface serving VLAN 105.Cevap
- Inspect the DHCP server scope for to verify if the address pool has reached full exhaustion.Cevap
- CManually configure the default gateway on the POS terminals to use an IP address within the range.
- DModify the host netmask directly on the central DHCP server to match the static IP assignment of VLAN 10.
Cevap
The network engineer should verify that a DHCP relay agent (IP helper address pointing to 10.10.10.2) is active on the VLAN 105 gateway interface and inspect the DHCP server scope to ensure available lease pool capacity.
When hosts receive APIPA addresses (169.254.x.x), it indicates that DHCP lease negotiation failed. For clients on VLAN 105 communicating with a DHCP server on VLAN 10, a DHCP relay agent (IP helper address) is required on the router interface to relay Layer 2 broadcasts across subnets as unicast traffic. Additionally, if the DHCP scope on the server is exhausted, no leases can be issued, resulting in the same APIPA fallback behavior.
Adım Adım Çözüm
Anahtar Kavram
Cross-subnet DHCP Relay and APIPA Troubleshooting