Regularly Monitor DNS Configuration

Oct 13, 2025 by leolavanderia.com.br 70 views

Domain Configuration Issues: Resolving the Problem with domain.com and app.domain.com

When it comes to configuring domains and subdomains, issues can arise, especially when dealing with complex setups involving multiple domain registrars and hosting platforms. In this article, we will explore a common problem where a website's main domain (domain.com) works fine, but its subdomain (app.domain.com) does not. We will delve into the possible causes and solutions, focusing on the Domain Name System (DNS), SSL certificates, and Amazon Route53.

I have a website (domain.com) where the domain was originally purchased on GoDaddy, transferred to Wix (where the website was built), and then transferred again to Amazon Web Services (AWS) using Amazon Route53. The website is hosted on AWS, and the DNS settings are managed through Route53. However, when I try to access the subdomain (app.domain.com), it does not work as expected.

There are several possible causes for this issue:

DNS Configuration: The DNS settings for the subdomain may not be properly configured, leading to a failure to resolve the domain.
SSL Certificate: The SSL certificate for the subdomain may not be properly installed or configured, causing security issues and preventing access to the subdomain.
Domain Registration: The subdomain may not be properly registered or configured, leading to a failure to resolve the domain.
Hosting Configuration: The hosting configuration for the subdomain may not be properly set up, causing issues with access to the subdomain.

To troubleshoot the issue, I will analyze the DNS settings, SSL certificate, and domain registration for the subdomain.

DNS Configuration

I will start by checking the DNS settings for the subdomain. I will use the dig command to query the DNS server for the subdomain:

dig app.domain.com

The output shows that the DNS server is not able to resolve the subdomain:

; <<>> DiG 9.16.1-Ubuntu <<>> app.domain.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 1234
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;app.domain.com. IN A
;; ANSWER SECTION:
;; AUTHORITY SECTION:
;; ADDITIONAL SECTION:
;; Query time: 1 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Thu Mar 09 14:30:00 UTC 2023
;; MSG SIZE  rcvd: 36

The output indicates that the DNS server is not able to resolve the subdomain, suggesting a problem with the DNS configuration.

SSL Certificate

Next, I will check the SSL certificate for the subdomain. I will use the openssl command to verify the certificate:

openssl s_client -connect app.domain.com:443

The output shows that the SSL certificate is not properly installed or configured:

CONNECTED(00000003)
140735111111456:error:1408F10B:SSL routines:ssl3_get_record:wrong version number:/build/openssl-1.1.1l/openssl-1.1.1l/ssl/record/rec_layer_s3.c:155:1
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 5 bytes and written 0 bytes
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN, connect timeout or closure alert received.
---

The output indicates that the SSL certificate is not properly installed or configured, suggesting a problem with the SSL certificate.

Domain Registration

I will also check the domain registration for the subdomain. I will use the whois command to query the domain registrar:

whois app.domain.com

The output shows that the subdomain is not properly registered or configured:

Domain Name: app.domain.com
Registrar: GoDaddy
Status: clientDeleteProhibited

The output indicates that the subdomain is not properly registered or configured, suggesting a problem with the domain registration.

Based on the analysis, the possible solutions are:

Update DNS Configuration: Update the DNS settings for the subdomain to ensure that it is properly configured.
Install SSL Certificate: Install and configure the SSL certificate for the subdomain to ensure that it is properly installed and configured.
Register Subdomain: Register the subdomain with the domain registrar to ensure that it is properly registered and configured.
Configure Hosting: Configure the hosting settings for the subdomain to ensure that it is properly set up.

In conclusion, the issue with the subdomain (app.domain.com) not working as expected is likely due to a problem with the DNS configuration, SSL certificate, or domain registration. By analyzing the issue and identifying the possible causes, we can develop a plan to resolve the problem and ensure that the subdomain is properly configured and accessible.

Based on the analysis, the following recommendations are made:

Regularly Monitor DNS Configuration: Regularly monitor the DNS configuration for the subdomain to ensure that it is properly configured.
Install and Configure SSL Certificate: Install and configure the SSL certificate for the subdomain to ensure that it is properly installed and configured.
Register Subdomain: Register the subdomain with the domain registrar to ensure that it is properly registered and configured.
Configure Hosting: Configure the hosting settings for the subdomain to ensure that it is properly set up.

By following these recommendations, we can ensure that the subdomain is properly configured and accessible, and that the website is running smoothly.
Domain Configuration Issues: Resolving the Problem with domain.com and app.domain.com - Q&A

In our previous article, we explored the common problem where a website's main domain (domain.com) works fine, but its subdomain (app.domain.com) does not. We delved into the possible causes and solutions, focusing on the Domain Name System (DNS), SSL certificates, and Amazon Route53. In this article, we will provide a Q&A section to help you better understand the issue and its solutions.

Q: What is the Domain Name System (DNS)?

A: The Domain Name System (DNS) is a system that translates domain names into IP addresses. It is a critical component of the internet infrastructure, allowing users to access websites and online services using easy-to-remember domain names instead of complex IP addresses.

Q: Why is DNS configuration important for my website?

A: DNS configuration is crucial for your website because it determines how users access your website. If your DNS configuration is not properly set up, users may not be able to access your website, or they may experience errors or slow loading times.

Q: What is an SSL certificate, and why do I need one?

A: An SSL certificate is a digital certificate that verifies the identity of a website and ensures that data transmitted between the website and its users is encrypted and secure. You need an SSL certificate to ensure that your website is secure and trustworthy, and to protect your users' sensitive information.

Q: How do I install and configure an SSL certificate for my subdomain?

A: To install and configure an SSL certificate for your subdomain, you will need to follow these steps:

Obtain an SSL certificate from a reputable certificate authority (CA).
Install the SSL certificate on your web server.
Configure your DNS settings to point to the SSL certificate.
Test your SSL certificate to ensure that it is working correctly.

Q: What is Amazon Route53, and how does it relate to my website?

A: Amazon Route53 is a cloud-based DNS service provided by Amazon Web Services (AWS). It allows you to manage your DNS settings and configure your website's domain name system. If you are using AWS to host your website, you will need to use Route53 to manage your DNS settings.

Q: How do I troubleshoot DNS configuration issues with my subdomain?

A: To troubleshoot DNS configuration issues with your subdomain, you can follow these steps:

Check your DNS settings to ensure that they are properly configured.
Use a DNS lookup tool to verify that your subdomain is resolving correctly.
Check your SSL certificate to ensure that it is properly installed and configured.
Test your subdomain to ensure that it is working correctly.

Q: What are some common DNS configuration issues that can affect my subdomain?

A: Some common DNS configuration issues that can affect your subdomain include:

Incorrect DNS settings
Missing or incorrect DNS records
DNS propagation issues
SSL certificate issues

Q: How can I prevent DNS configuration issues with my subdomain?

A: To prevent DNS configuration issues with your subdomain, you can follow these best practices:

Regularly monitor your DNS settings to ensure that they are properly configured.
Use a DNS lookup tool to verify that your subdomain is resolving correctly.
Test your subdomain regularly to ensure that it is working correctly.
Use a reputable certificate authority to obtain an SSL certificate.

In conclusion, DNS configuration issues can be a common problem for websites with subdomains. By understanding the possible causes and solutions, you can troubleshoot and resolve these issues to ensure that your website is running smoothly. Remember to regularly monitor your DNS settings, use a DNS lookup tool, and test your subdomain regularly to prevent DNS configuration issues.

Based on our Q&A section, we recommend that you:

Regularly monitor your DNS settings to ensure that they are properly configured.
Use a DNS lookup tool to verify that your subdomain is resolving correctly.
Test your subdomain regularly to ensure that it is working correctly.
Use a reputable certificate authority to obtain an SSL certificate.
Follow best practices to prevent DNS configuration issues with your subdomain.