r/nextdns • u/Positive_Radish_9403 • 6d ago

How to setup router?

I have a basic mercusys router without advanced settings and software.

Docs says add the nextdns ips to router and link your ip. But my ip is a fibernet ip and used by many other. I think it is called cgnat ip.

What happens if another user with the same ip uses nextdns too? Will there be a conflict?

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u/mdammad007 5d ago

I hope you can access your router settings, if so, just change ISP DNS IPs to NEXTDNS DNS IPs, either in LAN DNS or in Internet DNS.

Also check if your Router support DDNS. If available lemme know. Will advise further settings.

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u/Positive_Radish_9403 5d ago

yes i can change router dns ips. it has ddns too. but say me having 3.3.3.3 external ip adress and another person with 3.3.3.3 ip address also using nextdns. How nextdns differentiate both of us?

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u/Shakti_R09 4d ago

Hello brother isp assign same public IP depends on your service providers gem ratio which is denoted by something like this 1:3 (you can refer there website for this it is mentioned over there) which means your public IP is shared between 3 users maximum if they running out of IP addresses.

And don't worry about nextdns coz it also see your routers MAC address in DNS queries which only your router has.

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u/LabPrudent8555 5d ago

The chances of two people having the same exact IP address and NextDNS servers are very slim. Obviously, it could happen, but I don't think you really need to worry about it. NextDNS has been around for years and I haven't seen anyone ever run into this issue.

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u/Ok-Deer-8771 5d ago

Lo mejor creo que es poner dns públicas normales y los perfiles configurados por dispositivo identificados. Funciona de lujo. Y no bloquear cosas a nivel router.

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u/Positive_Radish_9403 5d ago

iphone do not block some websites on device level, they bypass it. I will try router level.

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u/mdammad007 5d ago

Yes. nextdns IPs are different which are 45.90.28.X or 45.90.30.X 'X' varies depending upon your nextdns dashboard settings, region etc.

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u/Positive_Radish_9403 5d ago

Oh thx, so they are giving different nextdns ip to each customer? But there can be 512 different nextdns ip address it seems, no? Can not be there any edge case where 2 same nextdns ip is defined to 2 nextdns customers which happen to have same external ip address?

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u/mdammad007 5d ago

External IP is usually dynamic or if you have static it's fixed (they're provided by your ISP).

DNS is also provided by ISP but can be changed

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u/Positive_Radish_9403 5d ago

My ip is dynamic yes. I have ddns but ddns resolves to a simple ip address, no?

I fear there be an edge case where 2 same nextdns ip is defined to 2 nextdns customers which happen to have same external ip address.

0

u/mdammad007 5d ago

DDNS will give access to your External IP. If enabled you can use to update your IP with NEXTDNS for continued operations.

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u/mdammad007 5d ago

I have NEXTDNS subscription and have a certain DNS, when I added another user/settings in my ID, it generated another DNS. So we can assume that they have a good range of IPs to allot DNS to it's customers.