Odd subnet requirement for LAN network when using local DNS Server

Odd subnet requirement for LAN network when using local DNS Server

Odd subnet requirement for LAN network when using local DNS Server
Odd subnet requirement for LAN network when using local DNS Server
2024-07-27 04:43:31
Model: Deco X55  
Hardware Version: V1
Firmware Version: Deco X55(US)_V1_1.5.3 Build 20240531

Hello,

 

I'm seeing a weird issue when using a local DNS server on my local subnet where Deco is making me used a /22 subnet (255.255.252.0) instead of using a /24 (255.255.255.0) as I desire.  The error given is that "LAN IP address and DNS server address (192.168.128.3) cannot be in the same subnet. Please enter another.

 

How does that make sense that 255.255.255.0 won't work but 255.255.252.0 would?   My expected subnet is 192.168.128.0/24, using IPs from 192.168.128.1 (the deco router).   I have the DHCP region set to 192.168.128.80-192.168.128.229 and have set the DNS server options to 192.168.128.3 (my local DNS server) as primary and 192.168.128.1 (the deco itself) as secondary.

 

My internet WAN config is static IP using IP and DNS server info from my ISP so there is no overlap whatsoever between Internet/WAN and LAN config here.

 

 

I don't undrestand how there is an error for a /24 subnet but its ok for a /22 subnet, surely the 192.168.128.3 is in both subnets.   It does work with the /22 subnet but i find it odd that I can't make it a proper /24 subnet.

 

Thanks!

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Re:Odd subnet requirement for LAN network when using local DNS Server
2024-07-29 03:54:49

  @schneids Did you try after removing the secondary DNS address?

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