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How to assign different DNS depending on wifi / IP (DHCP Server) - SG300

Hi All

 

I have a SG300 with the latest firmware. I have two modems attached to it via ethernet. DHCP is turned off on each modem so I'm using the SG300 to assign IP's via DHCP Server. Let me explain.

 

Modem 1 : LTE Modem with static IP 10.0.0.2

Modem 2 : DSL Modem with static IP 10.0.0.3

 

Both are wireless. When a device (mobile phone or laptop) links to 10.0.0.2, I want the DNS assigned by the DHCP server to be 10.0.0.2, and when a device is connected to the DSL 10.0.0.3 then I want the DNS assigned to be 10.0.0.3

 

So basically, a DNS must be assigned to a device based on the wifi it is connected to.

 

Is this possible? and if so please assist me on how to do it via GUI.

 

Thanks in advance

Kind Regards
---------------------------------------------------------------
Rashaad Sallie - (CEO & Chief Designer)
theimagehouse design studio
M: +27 72 599 6269
E: rashaad@theimagehouse.co.za
W: www.theimagehouse.co.za / rashaadsallie.com
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8 REPLIES 8

balaji.bandi
VIP Guru VIP Guru
VIP Guru

you setup this in DHCP server, what DNS to deliver to client based on the subnet.

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All the devices and IP’s have the same subnet of 255.255.255.0
Kind Regards
---------------------------------------------------------------
Rashaad Sallie - (CEO & Chief Designer)
theimagehouse design studio
M: +27 72 599 6269
E: rashaad@theimagehouse.co.za
W: www.theimagehouse.co.za / rashaadsallie.com
--------------------------------------------------------------

As per the Orginal post you have given information that you have 2 Subnet as below :

 

Modem 1 : LTE Modem with static IP 10.0.0.2

Modem 2 : DSL Modem with static IP 10.0.0.3

 

you can have different DNS for each subnet.

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aturawat
Cisco Employee
Cisco Employee

Hello ,

Hope you are doing.

Try to create two pools and then give the DNS ip address.

 

switch01#config

switch01(config)#ip dhcp pool network Workstations

switch01(config-dhcp)#dns-server

 

Regards,

Atul

Okay so as far as I can gather....this is what I have to do.

 

Make a different subnet for each modem

Modem 1 : LTE Modem with static IP 10.0.0.2, Subnet 255.255.255.1

Modem 2 : DSL Modem with static IP 10.0.0.3, Subnet 255.255.255.2

 

After doing this will the devices have access to everything on the network as normal ?

 

Kind Regards
---------------------------------------------------------------
Rashaad Sallie - (CEO & Chief Designer)
theimagehouse design studio
M: +27 72 599 6269
E: rashaad@theimagehouse.co.za
W: www.theimagehouse.co.za / rashaadsallie.com
--------------------------------------------------------------

 

 

yes with different DNS if you required each subnet have various DNS

 

and subnet is not correct

 

Make a different subnet for each modem

Modem 1 : LTE Modem with static IP 10.0.0.2, Subnet 255.255.255.0

Modem 2 : DSL Modem with static IP 10.0.0.3, Subnet 255.255.255.0

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  Hello @theimagehouse.co.za

Hope you are doing well!

I also want to remind that both DHCP pools on the switch must be created in separate VLANs in order to separate clients attached to the switch and distinguish which client to which subnet to assign ( Look at Capture3 file ).

You will need to allocate the vlans amongst the switch interfaces according to which port to which subnet to be assigned ( e.g. client connected to port 2 needs to take 10.0.0.2 subnet address then you assign vlan 2 to this port ).

You will have to set static routes both on the modems and switch in order to route packets to external networks.

 

 

Kind Regards!

 

 

Anton Gekov
Technical Consulting Engineer – Level 1
Global CX Centers – Small Business Support

I use a SG300-28 switch in L3 mode doing DHCP.  I have the switch pointed to a RV340 router for internet access and DNS.  What ever DNS is passed to the RV340 can be passed to the client or you can hard code the DNS in the RV340 router and pass both DNS entries to the client through the switch.

 

When it comes to DNS I only now use QUAD9, 9.9.9.9 as this is a secure DNS provided by IBM to automatically not to resolve bad DNS sites.  I recommend using this DNS only.

 

I am interested in Cisco Umbrella system but I am not sure how it works on small system like the RV340 router.  I noticed Umbrella is now in the firmware in the RV340 router.  This may be a better option which I have not explored.

 

What router are you currently using?  Still I think if you change to QUAD9 the problem goes away. One DNS for all.  Google QUAD9.

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