Securing DNS Traffic with dnscrypt-proxy on Linux

In the current landscape of internet security, safeguarding your DNS traffic is crucial. DNS, or Domain Name System, resolves the human-readable website names into machine-readable IP addresses. However, traditional DNS queries are unencrypted, exposing them to vulnerabilities such as eavesdropping, man-in-the-middle attacks, and spoofing. To enhance privacy and security, encrypting your DNS traffic is advisable. One of the tools that enable DNS traffic encryption is dnscrypt-proxy.

What is dnscrypt-proxy?

dnscrypt-proxy is a flexible DNS proxy that supports advanced DNS encryption protocols like DNSCrypt V2 and DNS-over-HTTPS (DoH). By encrypting DNS requests, dnscrypt-proxy boosts your online privacy and helps to prevent DNS-based attacks.

Here's how to install and configure dnscrypt-proxy across various Linux distributions using their respective package managers: apt, dnf, and zypper.

Installation Instructions

Debian and Ubuntu (Using apt)

Debian-based distributions like Ubuntu support package installation via apt. To install dnscrypt-proxy, first, make sure your package list is up to date:

sudo apt update

Then, install dnscrypt-proxy:

sudo apt install dnscrypt-proxy

Fedora (Using dnf)

If you are using Fedora or other RPM-based distributions that support dnf, you can install dnscrypt-proxy using the following commands:

sudo dnf makecache
sudo dnf install dnscrypt-proxy

openSUSE (Using zypper)

For openSUSE or SUSE-based distributions, zypper is the package manager. You can install dnscrypt-proxy with these commands:

sudo zypper refresh
sudo zypper install dnscrypt-proxy

Configuration of dnscrypt-proxy

After installing dnscrypt-proxy, it’s crucial to configure it to start encrypting your DNS traffic. By default, dnscrypt-proxy will use a public DNS server that supports DNS encryption, but you can tweak the settings as per your requirements.

Edit the Configuration File:

You need to edit the dnscrypt-proxy configuration file, typically found at /etc/dnscrypt-proxy/dnscrypt-proxy.toml. Open this file with a text editor using sudo privileges:
```
sudo nano /etc/dnscrypt-proxy/dnscrypt-proxy.toml
```
Configure the DNS Server:

Inside the configuration file, look for a section that lists the available DNS servers. You can choose a resolver from the list or add a custom resolver. Ensure the DNS server chosen supports DNSCrypt or DoH.
Restart dnscrypt-proxy:

After making changes to the configuration, restart the dnscrypt-proxy service to apply the new settings:
```
sudo systemctl restart dnscrypt-proxy
```
Set Up Local DNS Resolution:

Modify your system’s DNS settings to use 127.0.0.1 as the primary DNS resolver, which makes all your DNS requests route through dnscrypt-proxy.

You can do this typically by editing the /etc/resolv.conf file:
```
sudo nano /etc/resolv.conf
```
Add or modify the following line:
```
nameserver 127.0.0.1
```
Validate the Setup:

Ensure dnscrypt-proxy is working as expected by querying a DNS name:
```
dig example.com
```
Check the response to confirm that your DNS queries are resolved correctly.

Conclusion

Encrypting DNS traffic using dnscrypt-proxy enhances your online privacy and security significantly. By following these installation and configuration steps across various Linux distributions, you can protect your internet activities from potential DNS-based threats. Always keep dnscrypt-proxy and your Linux distribution updated to benefit from the latest security patches and features.