D-Link AX1500 Product Overview page 38

Section 3 - Configuration
Secondary DNS Server Enter the secondary DNS server IP address assigned by your
ISP.
MTU Maximum Transmission Unit (1280~1460) - you may need to
change the MTU for optimal performance with your ISP. The
default is 1400.
Advanced Settings... - Static IP
Address Mode
Displays your chosen address mode.
PPTP IP Address
Enter the IP address provided by your ISP.
PPTP Subnet Mask Enter the subnet mask provided by your ISP.
PPTP Gateway IP Address Enter the gateway IP address provided by your ISP.
Primary DNS Server Enter the primary DNS server IP address assigned by your ISP.
Secondary DNS Server Enter the secondary DNS server IP address assigned by your
ISP.
MTU Maximum Transmission Unit (1280~1460) - you may need to
change the MTU for optimal performance with your ISP. The
default is 1400.
Secure DNS Enable this option to use public DNS with encryption via DNS-
over-HTTPS (DoH).
DNS over HTTP Provider
Select the DNS-over-HTTPS (DoH) service provider: Google
or Cloudflare.
Allow Fall-back
Use your primary or secondary DNS server as an alternative if
the configured provider is not working.
D-Link R15 User Manual 33