HP 6125XLG Layer 3-Ip Services Configuration Manual page 28

[Switch-Vlan-interface1] ip address 192.168.10.99 255.255.255.0
# Enable common proxy ARP on VLAN-interface 1.
[Switch-Vlan-interface1] proxy-arp enable
[Switch-Vlan-interface1] quit
# Configure the IP address of VLAN-interface 2.
[Switch] interface vlan-interface 2
[Switch-Vlan-interface2] ip address 192.168.20.99 255.255.255.0
# Enable common proxy ARP on VLAN-interface 2.
[Switch-Vlan-interface2] proxy-arp enable
After the configuration, Host A and Host D can ping each other.
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