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Is there a simple dns proxy for centos 8 that can cache requests?

I am running a .net core app on linux and it sends http request to a Web server.

Currently name resolution take 300ms.

I would like to cut it down to 1ms. Can it be achieved with a dns proxy and which one requires minimum setup?

Boppity Bop
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2 Answers2

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Sounds like a good use case for either unbound or dnsmasq, both of which are caching DNS servers by design. I personally have the most experience with unbound, so I'll describe that here but guides for installing and configuring dnsmasq are widely available as well.

Installation is as simple as running yum:

sudo yum install unbound

Then, configure unbound by editing /etc/unbound/unbound.conf. A reasonable default would be the following:

server:
  access-control: 127.0.0.0/8 allow
  access-control: 10.0.0.0/8 allow
  access-control: 172.16.0.0/12 allow
  access-control: 192.168.0.0/16 allow
  aggressive-nsec: yes
  cache-max-ttl: 14400
  cache-min-ttl: 1200
  hide-identity: yes
  hide-version: yes
  interface: 0.0.0.0
  prefetch: yes
  rrset-roundrobin: yes
    so-reuseport: yes
  use-caps-for-id: yes
  verbosity: 1
  num-threads: 2
  private-address: 192.168.0.0/16
  private-address: 172.16.0.0/12
  private-address: 10.0.0.0/8

forward-zone:
   name: "."
   forward-addr: 1.0.0.1@53 # Cloudflare
   forward-addr: 1.1.1.1@53 # Cloudflare
   forward-addr: 8.8.4.4@53 # Google
   forward-addr: 8.8.8.8@53 # Google

This configures unbound to be accessible from all RFC1918 (private) addresses, and forwards all requests to Cloudflare and Google DNS servers. Once configured, restart unbound:

sudo systemctl restart unbound

And you should be good to go!

dwaler
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A DNS proxy would be a device that accepts DNS requests for another device and forwards them on the behalf of that device. DNS proxy is not really a real thing in the definition of a proxy you are referring to. It would be the same functions as a recursive DNS server.

That aside though, the DNS client on your Centos machine would already be handling what you are trying to solve. If it is constantly reaching out to an external nameserver for an address, the TTL for the record is likely lower than it should be. It should reach out to the name server once, then use cache until the TTL expires. If that isn't happening, it sounds like the DNS record.

DubStep
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