Tag: DNS record

DNS Network

What is TTL and why is it important?

In our article today, we will take a look at the TTL. So, if you want to learn more about its purpose and why it is so important, you are in the right place. 

TTL – What is its main purpose? 

The value that specifies the time period or the number of hops that a data packet is put up to be alive is called time-to-live (TTL). Either across the network or in cache memory. It will be terminated when this timer runs out or the data packet hits its hop limit. Data packets are not all the same; they differ in size and shape, but they all have a unique TTL. The amount of time data packets should decide the time needed to live in a device to perform their missions.

How does it operate?

Massive volumes of packets will be routed around routers if they are not regulated. To get around this, each data packet must have an expiration date or a restriction. This makes it easier to track their progress and figure out how long they’ve been there. Packets also move through network points to get to their destination. As a result, a TTL value is included in each data packet. Only if time or hops are available, do routers receive the packet and forward it to the next network point. If the TTL indicates that no more hops/time is available, routers will stop transferring it.

On the other hand, routers send an ICMP (Internet Control Message Protocol) message. It reports IP errors and points to the packet’s source IP address.

Why is TTL important?

TTL is a critical method for controlling existing data packets and network traffic. Every day, networks get larger and larger. As a result, the volume of data packets passing through them is enormous. Without a means to govern them (expiration date), millions of old packets that served their purpose many years ago may still be floating around, causing confusion.

Time-to-live is an essential tool for determining if data is still valid in situations such as networking and device cache memory, as we previously discussed. Data that has been determined to be no longer useful can be discarded.

TTL also allows you to obtain information about packets, such as the amount of time they spent traveling and the whole route they took. This is critical information in terms of security!

TTL in DNS

TTL (time-to-live) in DNS (Domain Name System) indicates how long a DNS record, such as an A record or an ALIAS record, is valid (in seconds) and how long a nameserver (recursive or secondary DNS server) can store it in its cache memory. The DNS record will be removed when the TTL reaches 0.

The DNS client must ask the recursive DNS server again and wait for it to perform a fresh DNS query to obtain the record in the case of a recursive DNS server. Following that, it will be cached again based on the TTL.

To update its DNS records, a secondary DNS server must check with the primary DNS server again and complete a zone transfer. Otherwise, it will be unable to answer to domain-related questions.

Conclusion

To summarize, the TTL value is a critical component that determines how long data is valid. It will indicate whether the information is current or needs to be updated soon. It facilitates data updating.

DNS DNS records Network

PTR record: Why should you care about it?

PTR record is one of the critical DNS record types that you should know. It is one of the few that warrants special attention. Why, we will see in this article. 

DNS record – what does it mean?

To start, let’s see what precisely the DNS records are. They are nothing more than text instructions. Its primary function is to instruct domain name servers on managing traffic to your domains and subdomains. In addition, the network for websites is the entire Internet. So, a DNS record is a single mapping that connects an IP address to a resource in DNS. They are organized into DNS zones and kept on nameservers.

What is a PTR record?

PTR records, also known as Pointer records, are a DNS record that links an IP address to a domain name. It is proof that the IP address being checked is indeed tied to the domain name and that it is not a hoax. So, it allows you to check and verify that the IP address you’re using belongs to the domain name. Furthermore, it demonstrates that it is not a hoax. Thanks to the Pointer record, verifying distinct pieces or services, such as a mail server, is simple.

Structure

The structure of the PTR record is simple and easy to understand. Here is an example how what it could look like:

  • TYPE: PTR record – It denotes the DNS record type. 
  • Host: 78.159.213.32 – You must provide the host’s IP address in this field. An IPV4 or IPv6 address is possible.
  • POINTS TO: example.com – You can use this field to show the domain name.
  • TTL: 1h – You set the TTL or time-to-live value here.

How to create a PTR record?

It’s simple to set up a DNS Pointer record. So, let’s break it down into steps.

  1. It would be best if you first built a Master Reverse Zone.

In a Master Reverse Zone, the PTR record can exist. However, it’s important to note that it shouldn’t be used in a conventional Master zone. The IP address in the Master Reverse Zone should always be in reverse order. For example, if the IP address is 32.213.159.78., you should enter it as 78.159.213.32. Regardless of whether it’s an IPv4 or IPv6 address, the same rule applies.

  1. The next step is to generate the Pointer record.

When adding the PTR record, you’ll also have to input it backward. You should have a matching A or AAAA record for each Pointer record. As a result, make sure to double-check!

  1. Finally, add the NS records.

NS records pointing to your nameservers should be added to the IP provider. Your Reverse DNS zone is now complete!

Why is it important to use rDNS service?

PTR record vs. A record

When we compare the A and PTR records, we’ll see that they’re polar opposites. This is because the A record links a domain name to an IP address (IPv4). On the other hand, the PTR record is used to resolve an IP address (IPv4 or IPv6) to a domain name.

It’s also worth noting that the A and PTR records are located in separate DNS zones. The A record should be added to a Primary (Master) DNS zone, but the PTR record can only exist in a Master Reverse DNS zone and operate.

Conclusion

By and large, the PTR is a really fundamental DNS record that you have to know. Start using it for your domain to lessen the number of bounce emails. It is not difficult. You could just follow the steps above. Good luck!

DNS DNS records

​TXT record – What is it and why do you need it?

If you are searching for the TXT record, you are probably interested in email security and all the methods of authentication and validation of a domain. So, Let’s not waste any more time and see what the TXT record type is all about!

​What is the TXT record?

The TXT record is a type of DNS resource record and serves to associate data with the domain. The data could be a human-readable text, or it could be different information about servers and networks that could be read by machines only.

Usually, DNS administrators create various TXT records to ensure the proper functionality of the email servers. That way, the emails that are sent could be verified, and their origin could be authenticated.

The TXT records can be hosted as most of the other DNS records inside a Forward DNS zone. You can host multiple TXT records for different purposes, which won’t create problems between them.

You can see the TXT record first mentioned and read more about it in the RFC 1035 by the creator of the DNS – P Mockapetris.

​Why do you need a TXT record?

The current uses of TXT records are the following:

  • Ownership verification. It is one of the easiest ways to prove that you are the owner of a particular domain. Many services ask you to add a TXT record to the domain name. If you are the administrator, you could be able to do it. If you are not, this will be impossible.
  • Sender Policy Framework (SPF). This is a mechanism for verification of the sender and reporting. It could lower the SPAM.
  • DomainKeys Identified Mail (DKIM). This is an encryption method that prevents email spoofing. It uses public and private keys and keeps the keys inside TXT records.
  • Domain-based Message Authentication, Reporting, and Conformance (DMARC). It uses a combination of the previous two, the SPF and DKIM, and creates behavior policies. It boosts security.
  • Zero-configuration networking DNS-based service discovery. It is used for fast network configuration.

​How to check your TXT records?

You can see all the TXT records for a hostname/domain name by performing a DNS lookup.

​On Linux

Open the Terminal and use the dig command to perform a TXT DNS lookup:

dig hostname/domain name TXTs

You need to change “hostname/domain name” with the one you want to see.

​On Windows

Open the Command Prompt and type the following command:

nslookup -type=txt hostname/domain name

​On macOS

Open the Terminal, and use the nslookup command to see the TXT record:

nslookup -type=txt hostname/domain name

​Inside any browser

You can also use any browser, including your mobile phone’s one, and use an online utility for TXT lookup.

You can try Mxtoolbox.

Open it, write the hostname/domain name, and press TXT Lookup.

​Conclusion.

Now you know that the TXT records could hold different information about the domain name. It is mostly a tool for domain authentication, but also it can be used to show that somebody has access to a domain and the right to modify its DNS records. It is often the case that big cloud providers require you to put a TXT record for your domain so that you can use their services with that domain name.

DNS DNS records

How To Use SPF To Protect Your Domain reputation.

The reputation of your business (domain) is an essential asset you must protect at all costs. It means a lot for your clients: trustability and reliability. These are strong triggers for them to pick you or to choose your competitors.

Crime techniques used on the Internet to cheat users get multiplied, and we must be very aware. In some cases, they use your positive domain reputation to defraud your own clients. 

​What is SPF?

The sender policy framework or SPF is a system for validating the legitimacy of an e-mail server. It’s a helpful and efficient system to avoid spoofing and to enhance e-mail servers’ reliability.

Having SPF, you can authorize the only e-mail servers that can send messages on behalf of your domain. 

​What is an SPF record?

To enable SPF, you have to add an SPF record for your domain name. An SPF record is a DNS record from the TXT DNS type. It holds the necessary information that allows verifying which e-mail servers are truly authorized to send messages from the name of your domain name.

Once the SPF record provides that information, the e-mail server can be verified, validated, or not.

Using the SPF record, specifically its qualifiers and mechanisms, you or your administrator can establish rules, as strict as you decide, to verify. 

DNS SPF mechanisms:

  • “include” allows adding more domains (like example.com to example.net) for sending e-mails from the mail servers of the domain where the SPF record is hosted.
  • “all”, all mechanisms after it are to be ignored.
  • “a”, if you pick A, it means the A or AAAA records have to match with the return path for e-mails to be allowed.
  • “ptr”, picking this means the PTR query has to be performed and to match the return path. Only if there’s a match, there’s allowance.
  • “mx”, picking this means an MX query has to be performed and to match the return path. Only if there’s a match, there’s allowance.
  • “exists”, used for complex queries.
  • “ip4”, checks A records exclusively to verify whether addresses correspond to the domain or not.
  • “ip6”, checks AAAA records exclusively to verify whether addresses correspond to the domain or not.

DNS SPF qualifiers:

  • “+” means PASS. Therefore, messages from the domain should be accepted. 
  • “-” means FAIL. Messages from the domain must be rejected.
  • “~” means SOFT TAIL. Messages from the domain should get a failed tag, but they can be allowed.
  • “?” means NEUTRAL. No policies are involved.

​How to use it to protect your domain reputation?

By enabling SPF, you will stop bad actors from sending e-mails from your domain. 

Your clients won’t receive malicious messages from your domain name, and you will avoid complaints and anger from them.

To prevent dangerous phishing is not minor. To be pointed as malicious, risky, or to be accused of stealing sensitive clients’ data can totally sink your domain’s reputation. 

Ensure that your legit messages successfully reach your clients and providers. 

You can plan the best promotions or punctually order new supplies. But if your messages can’t reach your clients or providers, results won’t be positive. This can happen because your e-mails go directly to the SPAM folder. If there’s no way to verify that your messages are legit, they can be discarded for security. 

Conclusion.

SPF is a great alley to protect your domain reputation. Avoid the risk of losing trustability, clients, or getting banned. Enable SPF!