Does your ISP run it's own recursive DNS servers ?

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Does your ISP run it's own recursive DNS servers ?


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pswapneel

Swapneel
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87
Location
NA
ISP
AS24186
Most ISP's/Network operators have outsourced DNS operations to quad/cloud DNS providers (8.8.8.8 - Google, 9.9.9.9 - Quad9, 1.1.1.1 - Cloudflare) as it's one less thing to worry about. I know, this is an old-school topic perhaps, but been very interested to know if your ISP runs their own DNS infrastructure. The reason this gets important to know is because DoH(DNS queries over HTTPS) will soon be enabled by all browsers. It has already been enabled by default by Firefox for users in the United States.

The best way to check if your ISP is running their own recursive DNS server - login into the router and check the WAN/Internet page which lists the WAN IP address, Subnet mast, Gatway and DNS(Primary/Secondary). The primary/secondary DNS server IP addresses would be the part that's relevant to this thread. This would work for PPPoE connections which I am assuming would be most in here.

In the case you've configured the connection in bridged mode, you can run ipconfig(Windows), ifconfig(Linux/Unix) and check for the primary/secondary DNS server IP addresses.

I'll start with my response - AS24186(Railtel) runs a DNS server(203.153.41.28) in anycast. It allows queries only from their network.
 
I have a local isp here in chennai called Limras Eronet (AS132556 - BLUE LOTUS SUPPORT SERVICES)
They run thier own dns server at 45.125.116.250 and 45.125.117.250.
Allows queries even from other networks.
They don't hijack dns queries like some other ISPs and I'm free to use any dns service I want.
 
@swapneelp

Does it really matter what DNS your ISP is providing?

Ultimately if one knows about DNS, one's going to end up choosing their own anyway.

Plus now we have Anonymized DNS:
 
@Dark_Nate

Does it really matter what DNS your ISP is providing?
Yes, it does. This information/data is purely as a matter of understanding whether ISP's in India are running their own DNS infrastructure. In addition, the entire internet is moving towards DoH. This means that whatever DNS provided by the ISP will get bypassed and will be sent to a quad DNS provider(Currently it is CloudFlare/NextDNS for Firefox). This further implies that when CF goes down, who do you think the user should complain to because their Internet is now broken ?

In general, knowing what DNS is being used will be of paramount importance - both for users and network operators.

Plus now we have Anonymized DNS:
I know and understand your line of thinking. However, it is also a fact that the common user of the Internet isn't going to use setup & run dnscrypt. For the common user of the Internet, DoH will takeover.
 
@swapneelp Well, the user needs to know to set up a fallback DNS from a different provider. I also prefer Cloudflare, but I do have Google DNS as fall back. I've never been robbed of DNS resolving ever.

Also, ISPs need to ensure fallback resolver is set up during installation and also in their own network configurations.
 
Yes my ISP uses their own DNS Infra.

Adding to the discussion on why DNS Infra is important for ISPs, many CDNs map using DNS. DNS helps in CDN decision making of which node will deliver traffic to users of the ISP.