Year: 2022

DNS Network

What is TTL and why is it important?

by Gia

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?

by Gia

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.

How to check your PTR record?

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

DKIM record – definition

by Gia

Once you get into the DNS game, you have to know the tools to play and face every challenge ahead. The DNS has its structure, but it can be adapted to your specific needs. The only way to enjoy the benefits of its flexibility is to play with its different “cards”. Let’s define the DKIM record to know what it has in store for you!

What is the DKIM record?

DKIM record or DomainKeys identified mail is defined as an e-mail security standard created for domains to prove the e-mails sent on their behalf are authentic. To enable it gives certainty about your messages’ trustability to recipient servers. This is not a minor contribution to security in the current times. DKIM also protects messages from being altered while traveling from the sender server to the recipient server. Basically, these important functions are achieved through cryptography.

How to create a DKIM record?

How does the DKIM record work?

The DKIM technology allows domains to sign outgoing messages using cryptographic authentication. When you enable DKIM, it will work through the use of two cryptographic keys, one private and one public. The private key will sign e-mails when they leave the sender server. The public key is published into the domain’s DNS record to be available for the recipient servers to authenticate the messages’ source and check the integrity of the messages’ body. If the signature gets verified by the recipient server (via the public key), the messages are considered authentic.

Let’s now be a bit more technical. As an administrator of a domain, you have to publish the cryptographic public key using TXT record format. This step is a must for recipients to verify the authenticity of the message’s sender. When the mail server sends an e-mail, DKIM will create a digital signature and attach it to the message’s header. 

At this point, for sure, you may wonder what exactly a digital signature is. Well, it’s a hash value, a unique line of text properly encrypted with the private key, that must remain exclusively in the administrator’s control. Otherwise, security can’t be guaranteed.

DKIM has, as a part of its functionality, multiple algorithms for generating this digital signature. Every detail linked to the signature’s production process is written in the message’s header. Additionally, two cryptographic hashes are included. One is connected to the defined headers and the other to the message’s body.

The sent e-mail travels and arrives at the recipient mail server. This triggers a DNS query to search the public key of the sender domain for verifying the message. The recipient mail server gets it and proceeds to decrypt the digital signature. The hash values can now be compared with the values within the message. A match of these values will define the authentication of the e-mail. Besides, the recipient mail server will confirm that the message was not altered in transit. Therefore, security for the recipient while accepting this e-mail is guaranteed.

Advantages of having a DKIM record

  • It’s easy to configure. An administrator can directly do it.
  • It’s an efficient shield against forged and dangerous e-mails. Through DKIM, you can secure the messages sent from your domain not to be altered and damage recipients and your reputation.
  • It helps to avoid phishing and spoofing.
  • It provides security to your domain’s mail server, and its possibilities can be expanded if you combine it with other DNS records like DMARC.

Conclusion

The DKIM record means security for your domain mail server and for your clients (recipients). It’s by definition a security ace you should have up your sleeve!

DNS DNS records

What is the purpose of the DMARC record?

by Gia

If you don’t feel like reading the 70+ pages of RFC 7489, but still you want to know more about DMARC, you came to the right place! I will simplify it for you and explain to you DMARC and the DMARC record in less than a few minutes!

What is DMARC?

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a mechanism that an organization can use to define domain-level policies and preferences regarding email handling. For example, message validation, disposition, receiving, and reporting.

The companies require a method of authentication of the domain names of the messages (emails) that they are receiving. They need to have rules and procedures based on the values that the emails and domain names can provide. Thanks to that, the receivers can check the messages and provide valuable feedback to the domain’s owner about the way its domain is used. The owner can see if there was any abuse of its domain.

DMARC uses two factors to set policies:

SPF (Sender Policy Framework) record. It is another email validation mechanism that offers to report. Using it, you can define who can send emails on the domain name’s behalf.

DKIM (DomainKeys Identified Mail) record. DKIM is a method of email encryption and authentication of the sender of the email, using the domain name. The receiver could use it and validate that an email comes from the right domain name.

The purpose of DMARC is to reduce phishing attacks, reduce spoofing attacks, and provide better security for email communication. In general, having DMARC will ensure the delivery of your emails and stop other people from abusively use your domain name for attacks.

What is the DMARC record?

The DMARC record is a DNS TXT record that sets the policies about the domain name based on the SPF record, DKIM record, and other parameters. It sets behaviors that the receivers of the emails, sent by a particular domain, should have.

The purpose of the DMARC record is to allow you, as the domain administrator, to set up the policies regarding the handling of the emails coming from your domain name.

The tags that the DMARC record uses are:

Adkim – behavior based on the DKIM record.

Aspf – behavior based on the DKIM record.

Fo – Fail option. Defines what a server should do in case of failure.

P – Policy. Indicates the policies that the receiver should apply.

Pct – Percentage. To what amount of emails should the policy be applied.

Rf – Report format. Defines the type.

Ri – Report interval. Demands reports after the specified time.

Rua – Return feedback (aggregate). Indicates where the report should be sent.

Ruf – Return feedback (mail specific). Indicates where the report should be sent.

Sp – Subdomain policies. If you want to indicate different policies for the subdomains than those for the domain name, you need to use this one.

V – just a simple version indicator. Currently, it should be DMARC1 because there is still no DMARC2 or more.

Conclusion.

So, knowing what DMARC record is, it is now time to implement it. Each additional layer of security keeps you safer—fewer problems and easier to manage. Ensure a secure exchange of emails, outgoing and incoming, with the power of DMARC!

DNS DNS records

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

by Gia

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.

How does TXT record work?

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