PLANET IPX-1980 - Manual (Page 66)

Please be remind: DNS response delay or no answer will effect the BLF
function un-normal working, so if your network connection not so stable, but
you still want the BLF function can works normal, we recommend to keep the
DNS item “Blank”.
6.2 Trouble Shooting
You can ping other network device through PLANET IP PBX and track network route by
command "Traceroute".
Click【System】--【TroubleShooting】to display the dialog as below:
6.3 DHCP Server Settings
ZX 50 series support DHCP , Click【System】--【Network Advanced】->【DHCP Server
Settings】 to show the following dialog:
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