In this article, I will discuss the difference between DNS cache and host file, two common methods for resolving domain names to IP addresses.
A DNS cache is a temporary storage of recently accessed domain names and their corresponding IP addresses, while a host file is a local text file that maps domain names to IP addresses.
I’ll explain both of these methods in more detail and highlight the advantages and disadvantages of each so you can decide which one is best for you.
What is DNS Cache?
Alright, let’s talk about the DNS cache. When we visit a website, our computer must translate the domain name (like google.com) into an IP address (e.g., 172.217.7.46) to communicate with the website’s server. The first time we visit a website, our computer has to perform a DNS lookup to find the corresponding IP address.
But here’s the thing: DNS lookups can take time and slow our browsing experience. That’s where the DNS cache comes in. DNS cache temporarily stores recently accessed domain names and their corresponding IP addresses.
When we visit a website we’ve accessed, our computer can look up the IP address in the DNS cache instead of performing a new DNS lookup.
This can speed up our browsing experience and reduce the load on DNS servers. However, the DNS cache has its limitations. It only stores recently accessed domain names, so if we visit a new website or a website we haven’t visited in a while, our computer will still need to perform a DNS lookup.
Additionally, the DNS cache can be vulnerable to attacks, as an attacker can manipulate the cache to redirect us to malicious websites.
What is Host File?
A host file is a local text file on our computer that maps domain names to IP addresses. When we type a domain name into our web browser, our computer first checks the host file to see if it has an IP address associated with that domain name.
It uses that IP address to connect to the website’s server if it finds a match. If it doesn’t find a match, it will perform a DNS lookup to find the IP address. The great thing about host files is that they can be customized to include our mappings, so we can override the default DNS settings and access specific websites or servers more quickly.
However, host files can also be cumbersome to maintain, as we need to manually add and update mappings whenever we want to access a new website or server. Additionally, if we have multiple devices, we must maintain a separate host file on each device.
Finally, host files can also be vulnerable to attacks, as an attacker can manipulate the file to redirect us to malicious websites.
Difference Between DNS Cache and Host File
Now that we’ve discussed the DNS cache and host file, let’s compare the two! The first factor to consider is speed. DNS cache is typically faster than the host file, as it doesn’t require us to maintain mappings manually. However, host files can be faster for websites or servers we frequently access, as we can customize the mappings.
The second factor is security. Both the DNS cache and host file are vulnerable to attacks. Still, the DNS cache is generally considered more secure, as our operating system manages it, and can be configured to use secure protocols like DNSSEC.
On the other hand, a host file is a local file that attackers can easily manipulate.
The third factor is maintenance. Our operating system automatically manages the DNS cache, so we don’t need to do anything to maintain it. Host file, however, requires us to manually add and update mappings, which can be time-consuming and error-prone.
The fourth factor is customization. The host file is more customizable than the DNS cache, as we can add our mappings to access specific websites or servers more quickly. On the other hand, the DNS cache is managed by our operating system and doesn’t allow for much customization.
The choice between DNS cache and host file depends on our needs and preferences. A DNS cache might be better if we value speed and security. If we value customization and don’t mind spending time maintaining mappings, a host file might be the way to go.
Conclusion
DNS cache and host file are two common methods for resolving domain names to IP addresses. A DNS cache is a temporary storage of recently accessed domain names and their corresponding IP addresses, while a host file is a local text file that maps domain names to IP addresses.
DNS cache is typically faster and more secure but less customizable and requires less maintenance. On the other hand, the host file is more customizable and requires more maintenance, but it can be faster for specific websites or servers that we access frequently.
Using a DNS cache or a host file depends on personal preferences and needs. Regardless of the chosen method, it’s crucial to understand the pros and cons and take precautions to prevent attacks.
Frequently Asked Questions
How Long Is DNS Cache Stored?
Positive and negative responses to queries are stored in the DNS cache for 86,400 seconds (i.e., 1 day) and 300 seconds (5 minutes). This means that if you visit a website once, Windows will store the DNS information for that site for up to 1 day.
If you visit the same site multiple times within that day, Windows will not need to query the DNS server again because it already has cached information. After 1 day, Windows will automatically remove the entry from the cache.
Likewise, if you try to visit a website that does not exist, Windows will store that information for 5 minutes before removing it from the cache.
Is It Safe To Flush DNS?
When you visit a website, your computer looks up the site’s IP address using a DNS server. DNS servers keep a record of all the addresses they’ve looked up so that they don’t have to look them up again each time you visit a site. However, over time, these records can become outdated or corrupted.
Flushing the DNS server will remove any addresses that aren’t valid, like ones that are out-of-date or have been tampered with. It’s also important to note that flushing the cache has no adverse side effects. It can improve your browsing speed and security by ensuring that you’re always using the most up-to-date DNS records.
So, if you’re having trouble accessing a website or suspect your DNS server may be compromised, clearing the cache is a good first step in troubleshooting the problem.
