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Title: How to set individual DNS-Server IPs per LAN-Interface DHCP-Scope on RG-EG series [Print this page]

Author: prueger@networx Time: 2023-6-1 02:57
Title: How to set individual DNS-Server IPs per LAN-Interface DHCP-Scope on RG-EG series
Dear Ladies and Gentlemen,

I'm using a RG-EG210G-P as Gateway and want to set my local DNS-Server IP (fE. running on Synology or Windows) as DHCP option for my internal LAN-Subnet (eg. 10.1.1.0/24) for being able to resolve internal ips/hostnames. The problem is, that the available DHCP-options are used by all other LAN Interface DHCP-Scopes too and I don't want to provide the same DNS-Server to the Public Guest Subnet (eg. 10.1.100.0/24) - the guest network should use some public DNS like google (8.8.8.8) for example because I don't want guests to access my internal DNS.

After research it seems that the RG-EG series doesn't provide DHCP-relay functionality correct? Is there any change to somehow provide a custom DNS-Server IP per LAN-Interface DHCP-scope? If I disable the DHCP for a specific LAN-Interface (eg. Vlan 1 - 10.1.1.0 DHCP off) and provide the DHCP running on an external local DHCP-server I'm able to provide the specific DHCP-option but I get an Alert via eWeb meaning something like "No active DHCP-Pool for Vlan - SSID may be not broadcasted..".

My Target-Configuration:

Vlan 1 (Internal LAN):
NetID: 10.1.1.0/24
DHCP-Option DNS: 10.1.1.9 -> Local DNS IP

Vlan 100 (Public Guest):
NetID: 10.1.100.0/24
DHCP-Option DNS: 8.8.8.8 -> Public DNS

Thank you very much for your support!

Author: javier@ruijie.c Time: 2023-6-1 08:23
Hi, sorry but on DHCP option we cannot set different DNS for each VLAN. However, this EG devices have DNS proxy feature. You can chek it on the configuration guide on page 50:
https://www.ruijienetworks.com/resources/preview/Ruijie-Reyee-RG-EG-Series-Routers-Web-based-Configuration-Guide-Release-ReyeeOS

Author: prueger@networx Time: 2023-6-1 12:30

Javier replied at 2023-6-1 08:23
Hi, sorry but on DHCP option we cannot set different DNS for each VLAN. However, this EG devices hav ...

Hi Javier,

thanks for your fast response and support!

Already tested the DNS-proxy feature before but as soon as I enable it and set the DNS-Server IP to my internal DNS-Server the DNS resolving stops working on my DHCP clients.

My setup:

Vlan 1 - 10.1.1.0/24
DHCP: enabled
Predefined DHCP Server 10.1.1.1 (RG-EG210G-P)
DNS-Proxy enabled
DNS-Server IP: 10.1.1.9 (local DNS server)

I get the following error message when executing nslookup: "reply from unexpected source: 10.1.1.9#53, expected 10.1.1.1#53". The client in this case is a MacBook Pro.

Thanks in advance,

all the best!

Author: liuwei8@ruijie. Time: 2023-6-2 10:02

Patrick P. replied at 2023-6-1 12:30
Hi Javier,

thanks for your fast response and support!

Hi

Sorry for the inconvenience, Reyee EG210G-P cannot set individual DNS-Server for per VLAN, it only supports one DNS server option for all VLAN, even use DNS Proxy cannot do that.

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