With the shortage of available address space in IPv4, IPs are becoming increasingly difficult to come by, and in some cases, increasingly expensive. However, in most instances, this is not a drawback. Servers are perfectly capable of hosting multiple websites on one IP address, as they have for years.
You may find the “can’t resolve hostname” or “temporary failure in name resolution” error when using retrieval command like wget, cURL, ping or nslookup. There are many reasons why these commands can cause an error, including file corruption. For the sake of brevity, we look towards commonalities between these commands to solve the issue.
These commands connect to the Internet using gateways to communicate and provide information. If the connection from your local machine, in this case, a CentOS server, is disconnected you’ll likely run into issues trying to access the world wide web. In this troubleshooting tutorial, we’ll show you some common solutions to connectivity issues.
Step 1: Amongst many other configuration tasks, the resolv.conf file is used to resolve DNS requests. Manually editing the resolv.conf file to configure name resolution will only do so temporarily. The Network Manager controls this essential /etc/resolv.conf file to create permanent changes. So, we’ll first stop and disable the Network Manager:
chkconfig NetworkManager off; service NetworkManager stop
Step 2: The method for permanent changes is to edit the /etc/sysconfig/network-scripts/ifcfg-eth0 file instead of resolv.conf file. Open the file:
Next, we’ll set our DNS IP’s to use Google’s Public DNS (126.96.36.199 & 188.8.131.52).
Save and quit the file using ESC and :wq.
Step 3: Enable and restart your network, using the commands associated with your server version.
CentOS 6, CloudLinux 6, RHEL 6:
chkconfig network on
service network start
CentOS 7, CloudLinux 7, RHEL 7:
systemctl enable network.service
systemctl start network.service
Step 4: Test the reachability of a host by using ping, curl, wget or any testing tool of your choice. In our example, we’ve successfully ping’d Google!
PING google.com (184.108.40.206) 56(84) bytes of data.
64 bytes from lga15s46-in-f14.1e100.net (220.127.116.11): icmp_seq=1 ttl=57 time=6.65 ms
64 bytes from lga15s46-in-f14.1e100.net (18.104.22.168): icmp_seq=2 ttl=57 time=6.68 ms
64 bytes from lga15s46-in-f14.1e100.net (22.214.171.124): icmp_seq=3 ttl=57 time=6.68 ms
You don’t have to rack your brain over connectivity issues! Liquid Web customers enjoy 24/7 support for our VPS Managed products. Our knowledgeable team of support techs have experience with solving errors of this nature. Access our support team through a ticket, chat or phone call!
Windows periodically checks for the latest updates and security features for your devices. Automatic updates are implemented with the intention of running your device smoothly and securely. With top security in mind, most Liquid Web servers are set to automatically install these updates thus saving you the task of remembering to implement critical updates or patches.
The vast majority of the times, windows updates complete successfully, keeping you and your customers safe. These updates rarely cause any server issues, but you may find that you want to roll back an update due to an unforeseen server change. Fear not, in this tutorial we’ll show you how to easily undo a Windows update on 2016, 2008R2 and 2012R2 servers.
Server 2016 with Windows 10
- Click on the Start button, search for Windows Update and hit Enter.
- Go to View Update History and select Uninstall Updates. Click the update you are wanting to uninstall/remove. (Generally, these are the most recent installs.)
- When the installed update window comes up, you can see the updates by name, KB number, type of program, version, and even the date of installation.
- Select the update and choose Uninstall. Follow the on screen instructions.
- Depending on the update, there may be a need to reboot the server to complete removal.
- While you are still in the Windows Update screen, select the offending update and click Hide Update. ** Once the Update is fixed and it is safe to install, then you can go in and manually install it on your system.
Complete the removal of the update by rebooting the server.
Server 2008R2 and 2012R2 with Windows 7/8
- Go to the Start button and select Control Panel.
- Go to Programs >> Uninstall a program.
- Select the program and right-click to Uninstall.
- Select the update you would like to revert.
- Select Yes to uninstall the selected update.
- Select the Restart Now button.
- While you are still in the Updates screen, select the offending update and right-click, to select Hide Update. ** To re-instate the update you can manually install it on your system.
Complete the removal of the update by rebooting the server.
Times are changing, and quite possibly, your hostname is as well if you are reading this article. You may have come across a scenario within the business that requires you to change your hostname. You might ask yourself why you would need to change your hostname? The most common scenarios would be due to a domain name change, your business has changed its course, or because you have thought of something better.
Sometimes you might forget to renew the domain names before they expire. Unfortunately, this can be a time when a domain broker purchases the domain name out from under you. These are agencies that take popular sites and purchase with the intent of holding the domain until their inflated price is met. As unfortunate as this may be, sometimes it is best to purchase a new domain name for cost efficiency.
What is DNS?
If you are new to web hosting, you may have heard the term DNS, but you might not be sure what it means or how it is essential to you. DNS is short for Domain Name System, and it is the process by which the whole Internet organizes and easier way for humans to reach websites.
Numbers or IP addresses identify all of the computers/websites connected to the Internet. While computers have no trouble identifying each other using these strings of numbers, it would be challenging for humans if we had to remember a set of numbers for every website we wanted to visit! Fortunately, DNS translates domain names like liquidweb.com to an IP address and back, so all we need to know to find a website is the name. For a more in-depth discussion of the DNS system, see Understanding the DNS Process.
You can use the DNS Tree for a quick, visual comparison of the records that exist on all of your nameservers. Making sure your records match across nameservers and that they match your server is an essential part of troubleshooting possible website issues. If you’re error messages like “This site can’t be reached” or “webpage is not available”, the DNS Tree may help you figure out where the problem exists.
How Do I Check My DNS?
Verifying accurate DNS records is essential for navigating traffic to the correct web server. You can use Liquid Web’s Internet Webhosting Toolkit to view your current, authoritative DNS records. Just go to the toolkit’s site, click on the DNS Tree tab, enter your domain name, and click Submit.
If you have registered your domain and set DNS records our tool will display the results in an easy to see “tree” of records, organized from most general to most specific.
In our example, we are looking up the records for liquidweb.com, so the tree begins with that domain at the far left of the screen.
The next set of records displayed are the Authoritative Nameservers for the domain. These are the servers designated as the holders of the records for this domain. If you want to change the records for this domain, you must change them on these servers. Changing records anywhere else won’t make reflect DNS changes. Your domain can have one, two, or as many Authoritative Nameservers as you would like but most websites use at least two for redundancy and stability.
The next set of entries in the DNS Tree show the Types of records that are available. DNS record types are unique for each kind of DNS function.
- An “A Record” is used to identify primary IP addresses of given domains.
- “MX Records” are used for email routing and delivery.
- “TXT records” hold additional information about the domain, like SSL validations, DKIM entries, or SPF records.
For more information about DNS record types, see DNS Record Types.
The final “column” of entries displays the actual DNS record. This is typically an IP address for an “A record”, and domain name for an “MX record”, or a string of text for a “TXT record”. Hovering the mouse over a circle will display all of the information for the record in a pop-out window, including the TTL, Type, and Data.
If you’ve made recent changes to your DNS records, the toolkit may be showing an older, or cached, version of the records. The TTL portion of the record indicates how frequently the DNS system should update its records. TTL is shown in seconds, so a typical setting of 3600 means that servers will be asked to update your records every 6 minutes.
The delay that occurs during this period is referred to as propagation. Some DNS changes, like nameserver changes, can take up to 72 hours to propagate, so if you are going to be making changes to your DNS records, you’ll want to lower your TTL values for a quick update. For more information on reducing your TTLs, see How To: Lowering Your DNS TTLs.
If you need additional help, Liquid Web customer’s can contact the Most Helpful Humans in Hosting via ticket, chat, or phone (1-800-580-4985) at any time and we’ll do our best to make sure everything is working correctly.
The security of your website is vital to the success of your Internet business. One way you can protect your data (and your customers) is through the use of encrypted communication protocols. Secure Socket Layer (or SSL) was the original method of providing for basic encryption between servers and clients. The industry mostly uses Transport Layer Security (or TLS) protocols now, but the process is basically the same, and most users refer to this kind of encryption by the old name: SSL. As part of our Web Hosting Toolkit, Liquid Web provides and SSL Tool to help you verify that your SSL is installed correctly and up-to-date. Below is an insight on how to use this tool and as well as some core concepts and certificates types to know when dealing with SSL.
SSL Certificate Checker
You’ll want to confirm that everything is functioning correctly on the server once you’ve successfully ordered and installed your SSL. At this time, you’ll want to check on your domain SSL’s to confirm expiration dates, covered subdomains, or other information. While you can use various third-party SSL checkers on the Internet, Liquid Web makes gathering this information about your domain simple. Just go to the Liquid Web Internet Webhosting Toolkit page and click on SSL Tool.
How Do I Check If My SSL Certificate is Valid?
Enter your domain name in the box provided and click on Submit. You can enter either your primary domain name (like mydomain.com) or any of the subdomains you may have created SSL certificates for (like blog.mydomain.com). If an SSL certificate is installed on the server for the domain, the page will display the status of the certificate and additional information.
In this example, you can see that the certificate is valid and trusted by browsers and that the tested domain matches the certificate.
You can also see which Certificate Authority issued the certificate and the dates for which the certificate is valid.
Finally, you can see which signing algorithm was used to generate the certificate (indicating how complex and secure the certificate is) and which domains and subdomains are covered by the certificate.
How SSLs Work
SSL connections work through a series of tools that exist on your server and on a client’s web browser. At the simplest level, the server and a client computer exchange information and agree on a secret “handshake” that allows each computer to trust the other computer. This handshake is established through the use of private and public SSL certificate keys. The private key resides on the server, and the public key is available to a client computer. All information passed between the computers is encoded and can only be decoded if the keys match. These keys are generated by a Certificate Authority (like GlobalSign) and can vary in complexity and expiration date. These matched keys exist to prevent what are known as “man in the middle” attacks when a third-party intercepts the Internet traffic for the purpose of stealing valuable data (like passwords or credit card information). Because the third-party doesn’t possess the matching keys, they will be unable to read any of the intercepted information.
By using a trusted certificate, your website users can enter their information with full confidence that their data is safe. Certificate Authorities only grant SSL certificates to operators who can prove that they are the legitimate owner of a domain and that the domain is hosted on the server for which the certificate is being issued. This proof is usually obtained by modifying the DNS records for a domain during the verification process of the certificate ordering transaction. To learn more about how to order an SSL through your Liquid Web account, see How To Order or Renew an SSL Certificate in Manage.
Types of SSL Certificates
While SSL certificates all provide the same essential functions, there are several different types of certificates to choose from. You’ll want to establish which certificate meets your needs before you decide to order one for your domain. The types we’ll discuss here are Self-Signed Certificates, Standard Domain Certificates, Wildcard Certificates, Extended Validation Certificates.
Most servers have the capability of generating a Self-Signed SSL certificate. These certificates provide the same kinds of encrypted communication that certificate provided by Certificate Authorities provide. However, because they are self-signed, there is no proof that the server is the “real” server associated with a website. Many control panels use self-signed certificates because the owner of the server knows the IP address of the server and can trust that they are connecting to the correct site when using that IP address. The advantage of self-signed certificates is that they are easy to generate and are free to use for as long as you want to use them.
Standard Domain Certificates
If you only need to secure a single domain or subdomain, a standard domain SSL certificate is appropriate. Standard certificates are generally the least expensive option from Certificate Authorities and are designed to cover one domain or subdomain (generally both domain.com and www.domain.com are covered by a standard certificate).
If you have multiple subdomains, you may be able to save time and money by getting a wildcard SSL certificate. Wildcard certificates cover a domain and all of its subdomains. For instance, if you have a domain website that also has a mail subdomain, a blog, a news site, and a staging site that you want to be protected by SSL communication, a single wildcard would protect all of the sites.
Extended Validation Certificates
SSL certificates are generally issued to companies that can prove they have the right to use a domain name on the Internet (normally because they can modify the DNS records for that domain). While that level of verification is sufficient for most companies, you may need to have additional evidence that your company is a reliable entity for business purposes. Organizational SSL certificates require additional vetting by a Certificate Authority, including checks about the physical location of your company and your right to conduct business. Organizational SSL details can be visible on your website if you install a Secure Site Seal. Additional vetting is available for companies that choose Extended Validation SSL certificates. Extended Validation processes are often used by banks and financial institutions to provide extra reassurance to their customers that their website is legitimate. EV SSLs will turn the address bar of the client’s browser green and display the company’s name on the right side of the address bar.
If you need help determining which type of SSL is right for your business, chat with our Solutions team for additional information.
Now that you’ve checked the details of your SSL certificate and confirmed that all of the information is correct, you’ll be sure that the communications between your server and your customer’s computers are secure as that information travels over the Internet. For more information about improving the overall security of your server, see Best Practices: Protecting Your Website from Compromise.
As part of our Web Hosting Toolkit, our Liquid Web IP Checker makes it easier than ever to identify IT issues. IP addresses are the unique numbers assigned to every computer that connects to the Internet. When troubleshooting connectivity issues, checking your computer’s IP address is the first step in identifying possible network issues. Correctly identifying your public IP address allows you (and our Support technicians) to find information on the server and it’s log files to pinpoint possible issues between your computer and server.
Finding Your Public IP Address
As the first piece of information in the connection between your local workstation and server, your Public IP address is critical to the information gathering process. Fortunately, you don’t need to navigate complex networking configurations on your computer to find the public IP address; you need to ask an external server what IP identifies with your connection. You can do this by using Liquid Web’s Internet Web Hosting Toolkit. Go to the toolkit website and click on IP Checker. You’ll immediately be shown the public IP address that your computer is reporting.
You can also get additional information about how your computer is identifying itself (including location, operating system, and browser details) by clicking on the link in the extra information area. This information can help identify website compatibility issues based on various user settings.
How Do I Know If My IP Is Public or Private?
Most computers that are attached to a network have both a Public and a Private IP address. The IP address assigned to your computer by your router or wireless modem is generally a Private IP and typically is in one of two “reserved” ranges: either 10.x.x.x or 192.x.x.x. These Private IP ranges allow all of the devices in your local network to communicate with each other. When connecting with devices outside of your local network, your router will provide a Public IP address to outgoing traffic (often all of the devices inside your network will “share” the same Public IP address). The Public IP address allows computers across the Internet to identify each other and communicate effectively. To troubleshoot networking issues, we’ll need to find the Public IP address that your computer is broadcasting to the Internet. With the Public IP you can search through the firewall and server logs to find connection attempts and identify possible issues that may be preventing access.
How Do I Know If MY IP Address Is Blocked?
Most servers have software that works to detect and prevent possible malicious activity. Sometimes this software is part of the firewall or another application, but the result is the same: computers that fail to satisfy this software will be blocked from accessing the server. These blocks can occur due to repeated failed login attempts or even by opening too many connections at the same time (this often happens when transferring a large amount of data via FTP).
Security software typically blocks IPs by an escalating scale. That is, an offending IP address will be blocked for a short amount of time on the first offense, but the blocks will increase in length as the behavior continues until the IP address is permanently barred. An incorrect password saved in an FTP client can result in a permanent block in a short amount of time. If you suspect your server is blocking your IP, you may be able to remove the block automatically. For more information on unblocking your IP, see Unblocking Your IP Address.
Now that you’ve got your Public IP address, you can check your server logs for failed connection attempts or other errors that may indicate why you are having trouble connecting. Or you can share that information with one of Liquid Web’s Most Helpful Humans in Hosting and they can help resolve whatever connectivity issues you are experiencing.
To learn more about the tools Liquidweb offers, submit a ticket with us via our firstname.lastname@example.org email, give us a call at 800-580-4985 or, open a chat with us to speak to one of our skilled Level 3 Support Admins today!
If there is one truth in the world of web hosting, it is that we always need more information. Information about configurations, dedicated servers, VPS servers, connections, delivery speeds and networking is essential in troubleshooting and optimizing our web presence. While this kind of information can be gathered from various providers and sites across the Internet, Liquid Web has developed a one stop shop toolkit to gather some of the most vital troubleshooting tools in one convenient interface designed to make your life easier.
The Liquid Web Internet Webhosting Toolkit provides you with the data you need to verify connectivity, identify DNS issues, and test web page performance. We’ll continue to develop and share new tools that will make your job easier; it’s one of the ways that we are working to be the Most Helpful Humans in Hosting. Continue reading “How Do I Use Liquid Web’s Hosting Toolkit?”
When using PhpMyAdmin, it’s essential to have the correct user permissions to create edits/writes to the database. Otherwise, insufficient permissions can lead to errors like the ones pictured below “#1044 – Access denied for user …[using password: YES]” and “#1045 – Access denied for user…[using password: YES]”. In our tutorial, we’ll show you how to correct this issue using the command line terminal. Let’s get started! Continue reading “Troubleshooting: MySQL/MariaDB Error #1044 & #1045 Access Denied for User”
What is a Redirect?
A redirect is a web server function that will redirect traffic from one URL to another. Redirects are an important feature when the need arises. There are several different types of redirects, but the more common forms are temporary and permanent. In this article, we will provide some examples of redirecting through the vhost file, forcing a secure HTTPS connection, redirection to www and non-www as well as the difference between temporary and permanent redirects.