Author: Ericsson

What is Ping command, and how to use it?

Commands DNS No Comments
What is Ping command

What is Ping command?

Ping command is a simple network utility tool. It has a command-line interface. You can write different commands and test various elements of your network – a computer on the network, the router, a particular domain, or IP address.
The ping command uses ICMP – Internet control message protocol. When you are performing a check, you need to set a target, and additionally, you can add options for the number of packets, continuous pinging, timeout limits, IPv4 or IPv6, and more.
You will get a response with additional statistics.
An ICMP request is a small packet of data that your computer will send to the target. The target should bounce it back and send an answer for each ping.
You can find the Ping command on Linux and macOS through the Terminal application, or on Windows, through the Command Prompt.
You should also be able to find it on Android or iOS/iPadOS through a third-party Terminal application. 

Ping command – examples, switches, and more!

How to use Ping command?

Continue reading →

CNAME record explained

DNS No Comments
CNAME record

The CNAME record is one of the first DNS records that you will read about when you are starting with DNS management. It has a very important task to do, showing the true domain name for the subdomains, making it really an essential DNS record. It saves time and makes it easier to manage the DNS.

CNAME explained completely

There are two parts in the CNAME’s name. C stands for canonical, and it wants to show which is the true domain name for the one that you are trying to resolve. The NAME is obvious. It stands for name, as in hostname.

The purpose of the CNAME record is to point one hostname to another. You can point different subdomains to the domain name. That way, you don’t need to add any other records for the subdomain because it will automatically redirect to the domain name.

If you have just a single DNS record for each subdomain, you will have far fewer DNS records, and the administration of your domain will be a lot easier.

CNAME records can be used to point:

www.domain.com to domain.com

blog.domain.com to domain.com

mail.domain.com to domain.com

newyork.domain.com to domain.com

Because of the way the CNAME record works, if the host (subdomain) already has other DNS records like A, MX, etc., you can’t create a CNAME record. And if you first create a CNAME record in the zone, you can’t create any other type of record in that zone.

Inside a CNAME record, you will see:

Host – the name of the subdomain that you want to point to the main domain name.

Type – CNAME.

Points to – the domain name. All of the CNAME records will point to this one.

TTL – time to live for that DNS record.

How to lookup a CNAME record?

If you are on Windows, the easiest and the safest way to check a CNAME record is to use the nslookup command. Go to the cmd (Command Prompt). Type “nslookup”, and press Enter. Now type “set type=cname”, and press Enter. The last pass is to write down the hostname, which you want to check. See this example, “mail.bing.com” and you will see the canonical name “star-bing-com.a-0001.a-msedge.net”.

If you are using Linux, go for the dig command. Open the Terminal and type “dig cname mail.bing.com,” and you will see the same “star-bing-com.a-0001.a-msedge.net” plus additional information. Dig command has very rich answers.

CNAME vs ALIAS

There is a newer type of DNS record called ALIAS that also points one hostname to another. It can do almost all that the CNAME can, but it can coexist with other records and can be added to the apex zone.

CNAME vs A record

The CNAME and the A records are very different. CNAME point one hostname to another while the A record points the domain name to an IP address. Also, if you want to resolve a domain, and first you get a CNAME, then you will need the A record too. So, the CNAME will take 2 queries instead of 1.

If you are interested in DNS records, check our article about the DNS CAA record!

Reverse DNS and PTR record – everything you need to know

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Reverse DNS

Reverse DNS is a key component of the configuration of your mail server. 

Not having Reverse DNS can mean not sending emails! Without well-configured Reverse DNS zone and PTR records, the rest of the email servers can’t check your domain’s IP address and discard your messages or throw them into the spam box.

Everything you need to know about Reverse DNS

A Reverse DNS is a service that provides Reverse DNS zones for your domain. The Reverse DNS zones serve to host PTR records that can be used for verification purposes, to check the IP addresses and if they lead to the correct hostnames.

The mail servers of other companies that want to send you emails need to make sure that the IP address that they are seen truly belongs to your domain. Otherwise, they can send the emails to another place, and criminals might use the information.

It is used for different services, too, for the same purpose to verify that a particular IP address belongs to the domain name.

The Reverse DNS can be used to point IPv4 or IPv6 addresses to hostnames. You can add both PTR records with IPv4 and IPv6 addresses inside the same Reverse DNS zone.

Why does the Reverse DNS matter?

The Reverse DNS matters because without it, your emails might not arrive at their destination. The mail servers of the receivers will check your PTR records, among other DNS records, and if they don’t find them, they might not trust your domain and discard the emails you are sending them.

Everything you need to know about the PTR record

The PTR record is the DNS type of record that you use for Reverse DNS and links IP addresses (it can work both with IPv4 and IPv6 addresses) to the domain name. When the receiving mail servers whats to check the origin of an email, they will perform a DNS Reverse lookup, and they will search for PTR records. The PTR records will guarantee that the IP truly belongs to the domain name.

How to perform Reverse lookup and PTR lookup?

You can perform a Reverse lookup using the nslookup command. The nslookup command is available on all popular computer OSes.

For Windows users, use the Command Prompt, and for macOS or Linux users, go for the Terminal application. There you will need to type the following nslookup command:

nslookup -type=ptr 91.198.174.194

We will specify the type of DNS record that we want, and for the Reverse lookup, we need the PTR record.

We are using the IPv4 address 91.198.174.194, but you can change it with whatever you like, so you can verify your domain or somebody else domain.

The result will be the name of the host. We can compare if this name is related to the domain we were expecting.

Conclusion

Now you know that Reverse DNS is and how it uses PTR DNS records to point IP addresses to domain names. Start using them for your domain and reduce the bouncing rate of your sent emails. It is not hard. It is just a matter of knowledge.

What is TCP?

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TCP (Transmission Control Protocol)

Transmission Control Protocol (TCP) is a communication standard, one of the first internet protocols (TCP/IP). It is connection-oriented, for all kind of devices and applications to exchange messages through a particular network. 

Data is organized in a specific way by TCP to be transmitted between client and server. The purpose is to protect the data on their trip around the network from the sending to the delivery.

TCP is a very popular protocol in network communications. 

How does it work?

Transmission Control Protocol (TCP) was created for sending packets on the Internet, making sure the proper data and messages’ are delivered through networks. It works through a process that involves different steps. 

As mentioned previously, TCP is connection-oriented. This means it has to make sure the connection between source and destination is not only set, but also kept until the whole exchange of data (sending and receiving of messages) is completed.

Thus, the first step is TCP sets the connection needed by a source and its destination. During this period, there’s a connection, but there’s not data transmission yet. 

Then communication starts. TCP gets messages from the sender (server or application) and split them up into packets. TCP organizes the chopped data with numbers to have control over all the packets and protect messages’ integrity. 

Already chopped and numbered, messages will go to the IP layer for transporting. They will be sent and re-sent by the different devices involved in the network (gateways, routers, etc.) until they reach their destination. All packets belonging to a message have the same destination. But they all can travel following a different route. 

As soon as they arrive, they are rebuilding. Yes, through the numbers assigned to every message’s packet, it puts all packets together again. 

Once messages are built, they are delivered to their recipient. 

You know that network congestion, traffic load balancing maneuvers, and other factors can affect networks’ performance. TCP can solve those problems if such causes affect packets and get duplicated, disordered, delivered, or lost. The protocol can identify the specific issue, then request the lost data to be transmitted again, and reorganize in the proper order, disordered packets.

If, after fixing problems, messages still don’t get delivered, the source is informed about the failure.

Without a doubt, Transmission Control Protocol (TCP) is a reliable standard and a key for the Internet to work better and more precisely. 

There are different protocols, but if you need accuracy and you can’t afford the loss of data (packets), TCP is ideal for you. That is why it is widely used by very well-known Internet applications like SSH (secure shell), FTP (file transfer protocol) or IMAP (message access protocol), SMTP (simple mail transfer protocol), HTTP (hypertext transfer protocol).

Advantages of TCP

  • It guarantees accurate end-to-end data delivery. The bytes received will be the exact ones (same order) originally sent. 
  • Its functionality includes not only issues’ detection (duplicated, lost packets, etc.), but also the ability to fix them.
  • It operates with network congestion avoidance, an algorithm that includes different mechanisms to control congestion problems (AIMD, congestion window, slow start…).

Disadvantages of TCP

  • It is focused on accurate delivery, and that takes time. TCP’s process and additional fixing of problems, in case they occur, can cause delays. We talk about seconds or milliseconds, but in the context of a demanding world (Internet), that can mean much.
  • It’s not a choice for real-time applications like voice-over IP or streaming media. The reason is TCP’s process doesn’t have a fast transmission as a goal.

Conclusion

TCP is a reliable tool, very popular on networks. If it is about accuracy for delivering data, no doubt TCP is the choice. 

DNS TXT record explained

DNS No Comments
DNS TXT record

There are a lot of DNS record types, at least 50 out there! One of them is called DNS TXT record, and it has a variety of purposes. Yes, it is one simple text record, but it is widely used, so let us explain the TXT record.

TXT record explained

TXT record is a DNS record type that has text information designed for external to the domain sources. The text could be written for people, so it would be easy to read, has enough information and logically organized, or made for computers, and has a more technical format.

Usually, you will see, inside the TXT record, a piece of general information about the domain and an additional part for a particular type of validation.

What’s inside a DNS TXT record?

There are just a few fields that you can manage:

  • Host: Hostname/ domain name, for which we are creating the TXT record.
  • Type: TXT – the DNS record type.
  • TTL: Time, that this record is cached on the recursive server.
  • Points to: Here, you can put a different value, depending on the purpose you decide.

Why do you need a TXT record?

The TXT DNS record has multiple purposes and can work with different software, including various email verification methods for incoming and outgoing email servers:

  • SPF – Sender Policy Framework is a method for authentication of emails, checking which of the servers has the right to send emails for a domain and has different mechanisms in case of wrong sender parameters.
  • DKIM – DomainKeys Identified Mail. It is a cryptographic authentication method for signing mails and proving that they are coming from a particular domain.
  • DMARC – Domain-based Message Authentication Reporting and Conformance is a security mechanism that proves who the sender of an email is and lowers the number of spam messages.
  • Verification for software – Big companies like Microsoft (Office 365), Google and more, need you to add a TXT record in your DNS zone to prove it is yours. It combines the SPF and DKIM authentication and works with them.

How to probe TXT records

We will use Wikipedia.org for checking their TXT records, but you can just replace it with your domain name and see your TXT records.

Check TXT record on Windows

Open the Command Prompt. Press “Windows key + R”, the Run application will start, and there you can type “cmd”, and press the Enter button. Inside the Command Prompt, we will use the nslookup command.

nslookup -type=txt wikipedia.org

Check TXT record on Linux and macOS

On Linux and macOS, there are many ways that you can check the TXT DNS record. All of them will involve using the Terminal application, so please start it. 

Dig command on Linux and macOS

Dig command is one of the most powerful tools for performing dns queries and debug your dns configuration, for example – what are your current TXT records. Here are some examples how to check the TXT record for a domain name:

dig wikipedia.org TXT

or you can use a specific one to check the DMARC record:

dig _dmarc.wikipedia.org TXT

Host command on Linux and macOS

host -t txt wikipedia.org

Conclusion:

After this article, you should know what the TXT DNS record is, why does TXT record exist, how to check the TXT record so we can easily say, TXT record explained! 

What is Time To Live (TTL)?

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Time To Live TTL

What is TTL?

Time To Live (TTL) sounds like a horror movie, but luckily it is not related to people. It is the value that shows how long the information should be kept in a particular device. There are many pieces of data that have their own TTL value. Here we will see DNS TTL and CDN TTL. 

When we are talking about DNS TTL, it is related to the time that the DNS resolvers must keep the DNS records in their cache. Each of the DNS records will have its TTL value. There are some with longer TTL because there is less chance that the value will change and others with shorter TTL value, where there are often changes. 

You can use these values as an orientation for your DNS records:

  • A and AAAA records – 2 hours (7200 seconds) is ok.
  • CNAME records – up to 12 hours (43200 seconds)
  • MX records – keep it as low. 1 hour (3600 seconds) is ok. 
  • TXT records – up to 12 hours (43200 seconds).

And about the CDN TTL, there we are talking about caching the whole content and how long should the cache servers keep the photos, videos, or whatever needs to be cached. 

When the TTL expires, the servers need to discard the current data that they have and make a new query to get the updated information from the primary servers. 

How does TTL work with DNS queries?

Talking about DNS requests, they are packets of data that also have TTL value. Imagine if they didn’t have such a parameter! The first-ever DNS query could still be around, going from server to server. 

So the TTL value of a DNS request is there to stop the perpetual search or answer and reduce pointless stress on the system. 

The value starts with a bigger number and gets dropped when it comes to zero by the routers. 

How to check the TTL value on Windows?

If you are a Windows user, you can use the Nslookup command and check a particular DNS record like – SOA, A, MX, AAAA, and more. Change the type with the one you want to see.

Start the Command Prompt as an administrator, and use this:

nslookup –types=soa yourdomainhere.com

How to check TTL value on Linux or macOS?

You have more options on Linux and macOS. You can use different commands through the Terminal application. 

The Dig command can show you different DNS records, and you can see their TTL value. This example will be with A DNS record.

dig a yourdomainname.com

You can also use the Host command in a very similar way:

host –a yourdomainname.com

This command will show you all of the visible DNS records with their TTL values.

Conclusion

The TTL value is a necessary part that limits the time a data is valid. It will show if the data is current or if it needs to be updated soon. It makes data updates easier.

 

DNS propagation explained

DNS No Comments
DNS propagation

Imagine this situation. You have finally decided to truly manage your DNS. You have selected a DNS service provider, you have created master and secondary zones, and you have added all the DNS records that you will need. You spend a lot of time and effort. And after everything is ready, you want to check and… there are no changes! Don’t worry. The DNS propagation takes time.

What is DNS propagation? 

It is a process to update the changes that you make in your DNS. After editing or creating new DNS records, they are saved in the authoritative DNS nameserver. That is ok, but what about all the rest of the DNS name servers? The cache memory of the recursive DNS servers will still keep the older versions of the DNS records based on their TTL value.
The DNS propagation is the time it will take to propagate, to update the changes to all of the recursive name servers.

Frequently asked questions about DNS propagation

Do you have any doubts about the DNS propagation, we hope you can find your answer here:

Could we make the DNS propagation faster?

Of course, we can, but there is a catch. Boosting the speed depends on the TTL value of the DNS records, so lowering the TTL value of each of the DNS records will indeed guarantee faster DNS propagation. The problem is that you might not want to have DNS records with low value. It will stress more your DNS servers, updating them too often.
We don’t need all of our DNS records to update all the time.
It is better to keep the records’ TTL values at their normal level. Plus, editing all of them will take a lot of time.

Can you check if the DNS propagation is ready?

Of course, we can, and this time there is no problem. You need to see if the IP address for a domain name has changed. This will indicate that the A or AAAA records are updated already.
We will show you different ways depending on your OS.

*Change yourdomainname.com with your actual domain name.

Linux or macOS

Open the Terminal, and we will use one of the built-in commands called the Dig command.

dig yourdomainname.com

You can use the host command too, whatever you prefer.

Windows OS
The Terminal alternative in Windows is the Command Prompt. Inside it, we will use the NSlookup command.

nslookup yourdomainname.com

How long can the DNS propagation take?

It can take a long time. Depending on when the recursive DNS servers updated themselves and the TTL values of the DNS records, it can take as much as 72 hours.

Conclusion

Waiting for the DNS propagation to occur is a time-consuming process that we could not fully predict. This is the situation, and there is little we can do, so just be patient, and in less than 72 hours, the update will happen.
Patience is the key here!

The Best Places to Buy a Domain Name

Domain names No Comments
buy domain name

If you already got the ideal domain name for your website, it’s time to register it! 

The process is easy, but you have to pick a registrar company to do it. Which one to choose is the first decision to be taken.

How to pick a domain name registrar? Tips

  • Check carefully TLDs prices (.com, .org, .net, .de). TLDs have different costs among them, and registrars also charge them differently.
  • Verify the initial price but also renewals. 
  • Understand the prices and conditions in case you want to take your domain to a different company.
  • Most web hosting companies also register domains. If you have thought already about a specific hosting provider, take a look at its prices and plans. Sometimes if you host your website, the register goes for free, at least the first year.
  • Check what kind of support the registrar offers. 

Best Places to Buy a Domain Name

The following registrars are accredited by Internet Corporation for Assigned Names and Numbers (ICANN).

Domain.com

It is a trustable company with 20 years in the business. It started as a domain name registrar. Later it became a web hosting provider too. 

You can pick between popular TLDs and more than 25 country code TLDs. Costs are a bit higher than average. For example, “.com” domain first year (registration) costs $9.99. Renewal price goes to $13.99 per year. “.net” initial price is $12.99. Its renewal, $15.99. TLD cost list is openly available for users.

There is 24/7 phone, email, and chat support.

Dynadot

Created in 2002, it’s a well-known domain registrar. It’s also a hosting provider.

Wide variety of TLDs. Average costs. TLD price list is openly shown. “.com” can be purchased by an initial price (registration first year) of $7.99 and its renewal, by $8.99 per year. “.net” initial price is $5.99, the renewal goes to $10.99.

Its search of domain name choices has extra tools like bulk and internationalized domain name (IDN), useful advanced options. You can get also results from auctions or domains that people no longer use. You can grab a domain used by someone and get it if it doesn’t get renewed. 

There’s grace deletion and free domain forwarding if you want to redirect users.

Support is available via chat, email, and phone. There’s an active forum with answers to common users’ questions. 

Namecheap

Founded in 2000, it is another reliable registrar that provides web hosting too.

It has a variety of TLDs to choose from. Competitive prices. The popular “.com” is rated at $8.88 the first year (registration) and $12.98 for renewal. “.net” is $10.98 for the first year and $14.98, the renewal.

Search for one or up to 50 domains every time. Results appear organized by new, popular, discounted, and international criteria. Get WHOIS for free.

Support is reachable through a live chat, and FAQ pages are at their disposal.

Hover

Created in 2008, it’s a younger and trustable registrar.

Many different choices of TLDs. “.com” costs $12.99 first year and $14.99, the renewal. “.net”, $15.49 registering price and $17.49, the renewal. Clear costs published. 

Search is easy thanks to its filters (different categories like food and drink, video and audio, businesses, etc.). WHOIS privacy is included for free, the time you stay with Hover.

There’s customer support via chat and email, but it’s not 24/7.

Conclusion

There are lots of registrar choices. Pick one with a positive reputation, and that can offer the best for your budget. 

It’s worthy of checking extras and special deals every registrar offers. 

CAA record explained 

DNS No Comments
CAA record explained

CAA record is a DNS record that shows who can be the Certification Authority for a particular domain and issue certificates.

What is Certificate Authority (CA)?

The CA is the entity that has the right to issue certificates like SSL certificates or TLS certificates. You can easily identify the CA, based on their name and their certificate revocation list (CRL). The Certificate Authority must provide a public key or a certificate from their CA if it is subordinate.

What is the CAA record?

The CAA record (Certification Authority Authorization) is a DNS record that a domain name owner can use to specify the certificate authority which can issue for their domain name. Inside the CAA, the domain owner can adjust the settings that cover the whole domain or just particular subdomains.

If you manage the CAA on a domain level, it will automatically apply on the subdomain level, too, unless you set it inside the record.

The CAA work with both wildcard certificates and single-name certificates. Separate and together too.

Why do you need to use DNS CAA record?

Continue reading →

Shared hosting – pros and cons

Web hosting No Comments
Shared hosting

A server hosts every website you visit daily to be available to you and people around the world. Without a web hosting service, sites can’t be viewed on the Internet.

If you want to start a website, choosing the type of hosting, provider, and plan that fits your needs will be a critical decision to be taken. Shared web hosting is a popular service that providers will offer you for sure.

What is web hosting?

All the files that websites are built of (themes, text, images, videos, different codes, etc.) must be saved on a server connected to the Internet to be displayed online.

Web hosting is the service that offers you the storage space on a server needed for your website to be available on the Internet.

What is shared hosting?

This is the most popular, accessible, and basic type of web hosting service. It means your website will be stored in a server, together with more websites, so yours will live there, sharing space and the resources of the server (storage, bandwidth, processor, RAM, etc.) with others. 

In simple words, your site will live with roomies around.

Every site can use a certain limit of server’s resources. Such a limit is defined by the plan you choose.

Shared hosting pros

Easy configuration

Most providers offer one-click features for users to install easily what they need. 

Built-in features

To make it simple for users, built-in features like DNS management and c-Panel (interface) are included to manage the site. No expert tech skills are required to do it. 

Recommended article: Anycast DNS vs Unicast DNS

Technical maintenance is not required from you

The company you hire is in charge of server maintenance, not you. Issues will be fixed by them. 

Customer support

You won’t be alone in this adventure. But since shared web hosting is a basic service, users will have almost nothing to modify or troubles to face in theory. How high or basic guidance you can get depends on the provider and specific plan you get. 

Cheap rates

Being the basic type of web hosting, it’s also the cheapest. Rounding numbers, starting rates can range from 3 to 10 monthly dollars. Providers offer initial discounts but always check the regular ones not to be surprised, once the discount period gets over.

Shared hosting cons

Sharing server’s resources

Resources divided among hundreds of clients definitely can affect websites’ performance. Websites with a heavy design or having traffic peaks can use a lot of processor’s power and RAM from the server. This can make your site’s loading time really sluggish.

Security issues

Sharing a server with many sites brings vulnerabilities. If a site gets compromised, potentially all the websites on that server could be hacked. If the attack goes directly to take over the server, all websites in it will be compromised.

Besides, all websites on a server share the IP address. In case another site does something wrong, it can be banned. Then, all sites using such an IP address can suffer the same consequences. 

No root access

Since it’s a service thought for beginners, you won’t have root access in case you want to modify settings for adding, removing, customizing, etc. 

Conclusion

Shared web hosting is a good beginning, especially if you own a site without much on-site interaction, a static site, a start-up, a blog, a corporative site, etc. It is an affordable, easy to manage choice.

Choose shared web hosting just if it really suits your website needs. If your site requires more resources and you pick shared hosting, for sure, you will face problems.

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