What does a DNS outage mean?

A DNS outage can ruin your day. Let’s think it’s the peak season for selling your business stuff. You already bought the big stock for selling, invested in Marketing to attract clients, enhanced the overall performance of your site, etc. And suddenly, the DNS is not responding. Clients can’t access your website. That’s tragic, isn’t it?

Domain Name System (DNS) outage means the time that the DNS is not available and, therefore, your domain. Without DNS working normally, your domain can’t be resolved to its associated IP address. Recursive servers won’t be able to do their job. When they ask the authoritative nameserver for the IP address, there won’t be an answer. If they try to search for it in its cache, the possibilities are high for it to be already expired (TTL), so it won’t work.

DNS outage is also called DNS downtime.

Common causes of DNS outages.

Human errors. Configuring DNS is a very delicate matter. A single typo can cause DNS downtime.
Maintenance routines. The normal maintenance required by authoritative nameservers can stop the DNS. Think about an update or a reboot. These common and needed actions for sure will stop (for a while) the capability of the name server to answer the DNS requests.
Lack of redundancy. It’s not rare to operate with only a DNS nameserver. The issue is that if it fails, goes out of service due to maintenance, or gets attacked, a DNS outage will be the consequence.
Cyber attacks. If your server gets targeted by a cyber attacker and you don’t have DDoS protection, or you can’t handle effective mitigation, the DNS outage will happen.
Data center issues. Servers are hosted in reliable premises to keep them safe. But even the safest data center can be a victim of a natural disaster. If a fire, flood, electric storm, etc., hits it, servers can be damaged or gone producing a DNS outage.

Is it possible to prevent a DNS outage?

Yes, it’s possible to prevent a DNS outage!

Automate human tasks. Avoiding human errors must be a priority. Technology solutions are many and available for you.
Increase the TTL of DNS records. Low TTL values will push resolvers to search for updates more frequently.
Get redundancy. The use of Anycast DNS or Secondary DNS servers is widely recommended. Through Anycast DNS, you will have a large network of servers globally distributed by your side. All of them will share the same IP address, the one of your domain. By adding Secondary servers, you will have extra copies of your DNS data on other servers. In both cases, if a server of the network goes down, there will be many more up (or at least another one) that could do the job.
Use DDoS protection. Cyber attacks happen very frequently. Shield your business not to suffer DNS downtime.

Conclusion

A DNS outage means unavailability and loss for your online business and pocket. Better prevent it!