DNS and Proxy Configuration Guide

This guide will show you how to configure DNS records and proxy settings to work with your Zerops applications, with specific implementation details for Cloudflare.

DNS Configuration

DNS records for Zerops services can be configured in two main ways:

• With Proxy: Routes traffic through proxy services, providing additional security and performance features (recommended for DDoS protection)
• Without Proxy (DNS Only): Direct connection to your Zerops service's IP address

DNS allows you to set two records based on IP address type:

• A record for IPv4 - Zerops offers either a free shared IPv4 or a paid dedicated IPv4
• AAAA record for IPv6 - Zerops provides a free dedicated IPv6

With Proxy

IPv6 only

Type    Name              Content                Proxy status   TTL
AAAA    <your-domain>     <your-project-ipv6>    Proxied        Auto

Note

Make sure your proxy service supports IPv4 to IPv6 translation for this configuration to work for both IPv4 and IPv6 users.

Do not add a proxied A record with shared IPv4 - doing so would prevent the proxy from properly routing IPv4 traffic to your service.

Dedicated IPv4

Type    Name              Content                Proxy status   TTL
A       <your-domain>     <your-dedicated-ipv4>  Proxied        Auto
# Optional
AAAA    <your-domain>     <your-project-ipv6>    Proxied        Auto

Tip

Adding also AAAA record can be beneficial as visitors with IPv6 support will connect directly via IPv6.

Shared IPv4 (valid but NOT recommended)

Type    Name              Content                Proxy status  TTL
AAAA    <your-domain>     <your-project-ipv6>    DNS only      Auto
A       <your-domain>     <zerops-shared-ipv4>   Proxied       Auto

Why not?

It does not make sense to expose your IPv6 address while proxying the shared IPv4. Use IPv6 only setup instead.

Without Proxy

Shared IPv4

Type    Name              Content                Proxy status   TTL
AAAA    <your-domain>     <your-project-ipv6>    DNS only       Auto
A       <your-domain>     <zerops-shared-ipv4>   DNS only       Auto

Both A + AAAA Required

Adding AAAA record is essential for shared IPv4 configuration as it serves as a security measure to prevent unauthorized domain claims.

Dedicated IPv4

Type    Name              Content                Proxy status   TTL
A       <your-domain>     <your-dedicated-ipv4>  DNS only       Auto
# Optional
AAAA    <your-domain>     <your-project-ipv6>    DNS only       Auto

Tip

Adding also AAAA record can be beneficial as visitors with IPv6 support will connect directly via IPv6.

IPv6 only

Type    Name              Content                Proxy status   TTL
AAAA    <your-domain>     <your-project-ipv6>    DNS only       Auto

Note

This configuration will only work for users with IPv6 connectivity, which may limit your service accessibility.

Wildcard Domain Configuration

Zerops supports wildcard domains (*.<your-domain>) that allow routing all subdomains to your project.

DNS Configuration

Method A: Direct configuration of A and AAAA records

Configure wildcard DNS records following the same patterns described in the DNS Configuration section, using *.<your-domain> in the Name field:

Type   Name              Content               Proxy status       TTL
A      *.<your-domain>   <your-ipv4-address>   DNS only/Proxied   Auto
AAAA   *.<your-domain>   <your-ipv6-address>   DNS only/Proxied   Auto

Method B: Using a CNAME record

First configure A and AAAA records for your main domain (<your-domain>), then set up a CNAME record:

Type    Name              Content         Proxy status       TTL
CNAME   *.<your-domain>   <your-domain>   DNS only/Proxied   Auto

Certificate Validation

For proper HTTPS certificate functionality with wildcard domains, configure:

Type    Name                            Content                     Proxy status   TTL
CNAME   _acme-challenge.<your-domain>   <your-domain>.zerops.zone   DNS only       Auto

This record enables Zerops to issue and verify a wildcard certificate for your domain.

Higher-Level Wildcard Subdomains

You can also set up higher-level wildcard subdomains like *.<subdomain>.<your-domain>:

Method A: Direct configuration

Type   Name                          Content               Proxy status       TTL
A      *.<subdomain>.<your-domain>   <your-ipv4-address>   DNS only/Proxied   Auto
AAAA   *.<subdomain>.<your-domain>   <your-ipv6-address>   DNS only/Proxied   Auto

Method B: Using a CNAME record

Type    Name                          Content                     Proxy status       TTL
CNAME   *.<subdomain>.<your-domain>   <subdomain>.<your-domain>   DNS only/Proxied   Auto

or

Type    Name                          Content         Proxy status       TTL
CNAME   *.<subdomain>.<your-domain>   <your-domain>   DNS only/Proxied   Auto

For certificate validation:

Type    Name                                        Content                                 Proxy status   TTL
CNAME   _acme-challenge.<subdomain>.<your-domain>   <subdomain>.<your-domain>.zerops.zone   DNS only       Auto

Combining Main Domain and Wildcard Domain

To use both <your-domain> and *.<your-domain>, specify both variants in your Zerops configuration. Zerops automatically issues a single shared certificate for both the main domain and all its subdomains.

Cloudflare-Specific Configuration

SSL/TLS Mode

Set encryption mode to Full (strict) or Full

• Ensures end-to-end encryption
• Full mode requires any SSL certificate (even if self-signed/expired), while Full (strict) requires a valid certificate

Certificate Management

1. Enable Edge Certificates to allow Cloudflare to manage SSL/TLS certificates
2. During initial setup, handle HTTPS settings in one of two ways:
   • Option A (Simple but Limited):
     • Disable Always Use HTTPS
   • Option B (Recommended for Production):
     • Keep Always Use HTTPS enabled
     • Create and enable a Configuration Rule, which disables Automatic HTTPS Rewrites for this specific path:

       Field: URI Path
       Operator: starts with
       Value: /.well-known/acme-challenge/
       This rule disables Automatic HTTPS Rewrites for the certificate validation path.

Validation Steps

Test your configuration:

# Check DNS resolution
dig AAAA <your-domain>

# Verify connectivity
curl -vI https://<your-domain>

# Test IPv4 access
curl -4 -v https://<your-domain>

# Test IPv6 access
curl -6 -v https://<your-domain>

Troubleshooting Guide

1. DNS Resolution Issues

   • Confirm correct record configuration
   • Verify proxy status settings
   • Check IPv6 address accuracy
   • Allow time for DNS propagation (typically 5-10 minutes)

2. Connection Problems

   • Test both IPv4 and IPv6 connectivity
   • Check proxy server status if applicable
   • Confirm port configurations

3. Certificate Issues

   • Verify proper _acme-challenge CNAME configuration for wildcard domains
   • Check that DNS records match the domains configured in Zerops
   • Cloudflare-specific certificate problems:
     • Verify Always Use HTTPS is disabled
     • If you encounter too many redirects or similar SSL errors:
       • Double-check that SSL/TLS encryption mode is set to Full or Full (strict), not Flexible
       • SSL mode might show incorrectly for newly added domains, try refreshing the page if settings appear incorrect

Technical Background

Understanding Shared IPv4 Addresses

Shared IPv4 allows multiple Zerops projects to use the same IPv4 address while maintaining separate routing for each project. Here's how it works:

1. When a visitor makes a request, it first arrives at the shared IPv4 address
2. The system looks at the domain name in the request (using SNI - Server Name Indication)
3. For security, it checks if this domain properly resolves to your project's IPv6 address
4. Only if IPv6 address matches your project will the traffic be routed correctly

This is why configuring both A (IPv4) and AAAA (IPv6) records is crucial when using shared IPv4 addresses - the IPv6 record acts as a security key that helps prevent unauthorized use of the shared IPv4 address.

Certificate Verification Methods

When issuing SSL/TLS certificates, different verification methods are used depending on the certificate type:

HTTP-01 vs DNS-01 Verification

• Regular certificates (for a single domain like <your-domain>) are typically issued using the HTTP-01 challenge method. This verification checks that you control the domain by placing a specific file at a specific URL.

• Wildcard certificates (for domains like *.<your-domain>) must be issued using the DNS-01 challenge method. This method requires creating specific TXT records in your DNS configuration.

How Zerops Handles Wildcard Certificate Verification

Zerops simplifies the DNS-01 challenge process:

1. You create a CNAME record (e.g., _acme-challenge.<your-domain> CNAME <your-domain>.zerops.zone)
2. When a certificate needs to be issued or renewed, Zerops automatically creates the required TXT records on its zerops.zone domain
3. The certificate authority verifies these TXT records through the CNAME redirection
4. Once verified, the wildcard certificate is issued without requiring manual intervention