Google Chrome browse is not using my host DNS settings.

Environment –
Operating System : CentOS release 6.8
Google Chrome: Version 55.0.2883.87 (64-bit)

I have an Intranet DNS server with internal domain name. The domain name is resolved internally by my DNS server to an internal private IP address. With Firefox I could always visit my internal site without issues, but recently I installed Chrome browser into my CentOS desktop and when I tried to visit my internal site, it was directing me to an Internet site which I don’t own. Apparently Google Chrome was ignoring my dns setting and using its own name servers.

My first attempt – flush DNS on Chrome (failed)
I went to the DNS configuration for chrome and cleared host cache. The dns settings clearly showed my ‘nameservers’ as the 192.168.1.1 (my internal name servers) and yet Chrome was not using it. Even after cleaning the host cache and flushing sockets, it didn’t help.

Chrome setting to view and manage DNS settings –

chrome://net-internals/#dns

My second attempt – block IPv6 (worked)
After running tcpdump on port 53, Chrome was calling an IPv6 address 2001:4860:4860::8888 to resolve domains.

Added below lines to

 /etc/sysctl.conf 

in order to disable IPv6 temporarily for a test –

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

And executed the command

 sysctl -p 

to apply the new kernel settings. After this change and flushing dns, I was able to visit my internal site.

I am guessing the DNS IPs used by Chrome as somehow internally coded, and haven’t been able to find those settings.

References –

https://www.reddit.com/r/chrome/comments/1xj69t/chrome_ignoring_system_dns_and_using_google_dns/

https://www.howtogeek.com/197804/how-to-clear-the-google-chrome-dns-cache-on-windows/

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