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Archimedes Trajano
Asked: 2019-10-08 06:04:13 +0800 CST

How can you change the DNS server used in VPC?

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I made a mistake in my configuration and set up my VPC to 10.0.0.0/16 and that conflicts with some of the services run in docker which created an internal network which now has a few containers at 10.0.0.0/24.

I was wondering if I can simply change the DNS to point somewhere else or do some routing to enable it like

route 10.253.0.2/32 to 10.0.0.2/32 on the management console and change /etc/resolv.conf? I tried to see if I can add the route, but won't give me the option of setting an IP

amazon-web-services

1 Answers

  1. Best Answer

    You can't use any routing tricks or change the DNS resolver's IP address in a VPC -- one of them is always the CIDR block base address +2 -- but perhaps you can use the other one, which is always 169.254.169.253 in every VPC.

    If [the enableDnsSupport attribute] is true, queries to the Amazon provided DNS server at the 169.254.169.253 IP address, or the reserved IP address at the base of the VPC IPv4 network range plus two will succeed.

    https://docs.aws.amazon.com/vpc/latest/userguide/vpc-dns.html

    It will be better in the long run to fix your configuration and use addresses in docker that are completely outside the VPC CIDR block.

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