The hosts file is a plain text file which maps hostnames to IP addresses. This file has been in use since the time of ARPANET. It was the original method to resolve hostnames to a specific IP address. The hosts file is usually the first process in the domain name resolution procedure. Here is an example of a hosts file entry.
When your company hosts a website or web app online, whether it’s an individual dedicated server or a whole server cluster, you naturally expect to have uninterrupted access at all times. However, it’s possible that in rare circumstances, your server could accidentally block your IP and prevent you from connecting and using the service.
If that has happened to you, this quick summary will provide you with all the essential information needed to verify the status of your IP. Additionally, we will offer some of the most common reasons for being blocked, as well as a few suggestions on how to unblock and whitelist your IP as quickly as possible.
The Domain Name Service (or DNS) is the key to the presence of your server on the internet. You are probably aware your domain has an “IP” address, which stands for Internet Protocol; that number is your domain’s literal web address on the internet. A typical IP address is a series of four numbers called octets that are identified like so: 10.10.10.10. You can think of your IP address as being similar to a postal address. The IP address is the exact location where your domain lives. I usually explain it like this;
Reading Time: 5minutesThis guide will walk you through the steps for setting up a firewall using iptables in an Ubuntu VPS server. We’ll show you some common commands for manipulating the firewall, and teach you how to create your own rules.
Reading Time: 3minutesAs 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!
Reading Time: 2minutesIf 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.
You may be working from a local machine that has an IP that is not scoped on that RDP port, making it impossible for you to gain remote access to add the IP address to the RDP rule’s scope. Do not fret; there is a simple and quick way to add your IP to the RDP scoping (or any other entities such as MySQL or MSSQL) right through your Plesk interface in your local browser. You can watch this video, or scroll down for step-by-step directions.
For security purposes, it is always recommended that you scope off your Remote Desktop Protocol (RDP) connection on your server. Putting a scope on the RDP rule in the Windows Firewall will allow only the indicated IP addresses to gain access to the server through Remote Desktop Protocol. The issue is that many of us do not have static IP addresses, but rather Dynamic IP addresses. This means that while once our IP address may be 120.32.111.01, it may change to something like 95.42.121.01 later. So if you were to add 120.32.111.01 to the RDP firewall for a customer or a system administrator, then you may need to add another rule for a different IP address.
Adding Your IP in Plesk
Step 1: Log in to Plesk
First, we need to make sure we know how to get to that Plesk login page. By default, the Plesk login page is https://<YourServerIP>:8443. For example, https://127.0.0.1:8443
We should arrive at a page with this in the center. Go ahead and type in Admin for the username and your password for Plesk. Usually, that password is set up by our team and is the default Server Administrator Password. Sometimes the username is Administrator, depending on a few variables. But one of the two user names should be fine.
Step 2: Tools & Settings
The first thing we need to do after we log into Plesk through the previous page is to navigate to the Firewall Rules. Go ahead and click on Tools & Settings. It will be located in the right sidebar near the bottom as shown below.
Step 3: Firewall
Once we pull up Tools & Settings go ahead and click on our destination, Firewall. You will find that option under the Security section. It will be the second option, just under Security Policy.
Step 4: Firewall Rules
After we are in the Firewall management, go ahead and click on Firewall Rules. This is where we will add the rule to allow a certain IP address to gain RDP access.
Step 5: Add a Firewall Rule
Under Tools, after going into the Firewall Rules, we will see the option labeled Add Firewall Rule. Go ahead and click on that, bringing us to our next step.
Step 6: Add Detail the New Rule
This is the page that we see after clicking on Add Firewall Rule. It can seem to be complicated and intimidating for some beginner level System Administrators, but it is simple.
If you or your client are not sure what that IP address that needs RDP access is, Liquid Web has a great site to visit that will display your IP address.
Here is an example of what you will find at https://ip.liquidweb.com.
While this particular example IP will not be the one that the customer or the System Administrator will see, (when visited on the local machine) the page will display the IP address that needs to be added to the rule for this RDP session to connect. That will be the only information that will be displayed on this page. Simply copy that IP address and use it in the instructions below.
Once you enter the IP address into the text box under Remote addresses, you do need to click the ADD button before clicking on OK.
As mentioned above, after clicking the ADD button while the IP address is entered into the Add an IP address or a network text box, it will be placed into the left text box. After that step, you will then be able to click OK to apply this rule to the firewall for the server.
Step 7: Connect to RDP
The individual at that IP address can now access the server via RDP. If you would like to review an article explaining how to use Remote Desktop Connection, or if you need further assistance, you can locate more info at our internal help center after logging into your Liquid Web account.
Congratulations! You now know how to add an IP address to an RDP rule that will allow a user to connect if the RDP is scoped off to the public. This can be done many times. Although Plesk does not allow you to edit the rule, you will have to create a new one each time. But this shouldn’t cause any issues. Also, keep in mind that this method can be used for any port, including MySQL and MSSQL.
In some ways, firewalld on systemd systems is easier to manage and configure than iptables. There are, for the most part, no long series of chains, jumps, accepts and denies that you need to memorize to get firewalld up and running in a basic configuration. The rules are simple and straightforward, but there is no reason you cannot still have all the power that iptables afforded.
Reading Time: 11minutesThe command line terminal, or shell on your Linux server, is a potent tool for deciphering activity on the server, performing operations, or making system changes. But with several thousand executable binaries installed by default, what tools are useful, and how should you use them safely? Continue reading “Useful Command Line for Linux Admins”→
Reading Time: 4minutesRemote Desktop Protocol (RDP) is the easiest and most common method for managing a Windows server. Included in all versions of Windows server and has a built-in client on all Windows desktops. There are also free applications available for Macintosh and Linux based desktops. Unfortunately, because it is so widely used, RDP is also the target of a large number of brute force attacks on the server. Malicious users will use compromised computers to attempt to connect to your server using RDP. Even if the attack is unsuccessful in guessing your administrator password, just the flood of attempted connections can cause instability and other performance issues on your server. Fortunately, there are some approaches you can use to minimize your exposure to these types of attacks.Continue reading “Improving Security for your Remote Desktop Connection”→