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[Solved] Temporary failure in name resolution

DNS errors such as temporary failure in name resolution can easily cripple your server. You will not be able to install any yum packages, you will even not be able to ping google.com, because as you can see this is a name resolution error, which means your server can not resolve domain names to their respective IP Addresses (if you know about DNS, you will know that this is something the whole internet relies on).

 

In this article we will see how to resolve temporary failure in name resolution error, we will discuss various reasons and their respective solutions.


Missing DNS Server IPs

 

Every server needs IP of DNS servers to which they can send their DNS queries. So if IPs of DNS servers are not configured then your server doesn’t know how to resolve domain names to IP Address thus you will end up getting temporary failure in name resolution.

 

In UNIX based system (Linux servers). DNS servers are usually configured in a file called /etc/resolv.conf. So if you don’t have this file or it is empty then you can not resolve domain names, make sure to create one and put the following contents in it:

 

nameserver 1.1.1.1
nameserver 8.8.8.8

 

Network Manager

 

Recently most of the Linux based servers are shipped with NetworkManager. NetworkManager help your connect your server automatically to the internet, for this task network manager auto-generates some configuration files. NetworkManager reads your interface file (eth0 or ifcfg) and then auto-generates /etc/resolv.conf file.

 

Now if you have not defined DNS servers in your /etc/sysconfig/network-scripts file, then /etc/resolv.conf will remain empty, thus you end up getting temporary failure in name resolution error. You can also fix this issue by just populating /etc/resolv.conf file as described above.

 

Also, make sure that in your /etc/sysconfig/network-scripts file set NM_CONTROLLED=no. So that NetworkManager will not update your /etc/resolv.conf file again.

Having issues installing packages on Ubuntu

 

You might see something like

 

Err:1 http://security.ubuntu.com/ubuntu xenial-security InRelease
Temporary failure resolving ‘security.ubuntu.com’
Err:2 http://dl.google.com/linux/mod-pagespeed/deb stable InRelease
Temporary failure resolving ‘dl.google.com’
Err:3 http://mirrors.digitalocean.com/ubuntu xenial InRelease
Temporary failure resolving ‘mirrors.digitalocean.com’
Err:4 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease
Temporary failure resolving ‘mirrors.digitalocean.com’
Err:5 http://mirrors.digitalocean.com/ubuntu xenial-backports InRelease
Temporary failure resolving ‘mirrors.digitalocean.com’
Err:6 https://repos.sonar.digitalocean.com/apt main InRelease
Could not resolve host: repos.sonar.digitalocean.com

 

This is an example of temporary failure in name resolution error, as apt can not resolve these mentioned domains to their IP Address. Make sure to allow these ports in UFW using the command below :

 

sudo ufw allow out 53,113,123/udp


Restrictions in your Firewall

 

There might also be a firewall restriction preventing your DNS queries. That is why we always recommend installing CyberPanel for free, CyberPanel will open all default ports for you, it will also help you run a super-fast website. Install CyberPanel for free using the install guide. You can also learn how CyberPanel will help you run the super fast website by reading our OpenLiteSpeed vs NGINX article.

 

Let see if this is actually a firewall error by stopping the firewall.

 

Firewalld

 

systemctl stop firewalld

 

Or CSF

 

csf -f

 

Now test and see if your issue is resolved if so, it means that your firewall is preventing your DNS queries.

 

Fix for Firewalld

 

You can add port 53 (UDP) and 43 (whois) to your firewalld. Following commands can be used

 

firewall-cmd — permanent — add-port=56/udp

firewall-cmd — permanent — add-port=43/tcp

 

This will open DNS related ports in FirewallD. If you are using CyberPanel you can easily go to CyberPanel firewalld interface and add these ports without going to CLI.

 

Go to -> https://<IP Address>:8090/firewall/

 

There you can easily open these two ports.

 

Fix for CSF

 

Open file /etc/CSF/csf.conf, then find the line containing TCP_IN and TCP_OUT then add your desired ports. Once your desired ports are added simply restart CSF so that your changes can take effect

 

csf -r

 

To remove any ports, you can just remove those ports from same lines and restart CSF.

 

Again if you are using CyberPanel and you have installed CSF (this will disable Firewalld interface). You can easily go to -> https://<IP Address>:8090/firewall/csf

 

From there you can add your ports and CyberPanel will take care of everything.


Wrong permissions on /etc/resolv.conf file

 

In some rare cases it is possible that your resolver file have wrong owner or permissions, execute following commands to implement correct permissions

 

chown root:root /etc/resolv.conf

chmod 644 /etc/resolv.conf

 

This should fix any permissions related issues with the resolver file.


Conclusions

 

I hope by now you have a general idea of what actually is a  temporary failure in name resolution error, because to fix any error we first need to know what actually it is. Then we’ve also discussed various ways to fix this error in different situations.

 

If you are a system administrator, then the first rule to solving any problem is stay calm and debug the problem. However, if you don’t have much time and looking for experts to manage your server, you are in the right place, you can hire our managed vps service. We offer 3 days free trial (no credit card required).

[Solved] Disk Quota Exceeded

Disk Quota Exceeded is very scary and common linux error in web hosting servers. When this happen you as a website owner may fail to restart mysql database, fail to upload file or even failed to restart your web server if it is down.

 

Generally it looks like you exceeded your alloted disk limit or your overall disk space is full as the error message is very obvious (Disk Quota Exceeded) meaning you reached the limit of your disk quota assigned to you.. Due to which various services like MySQL database and web server can’t start as they need to create files for their proper functioning. We at CyberHosting use CyberPanel control panel, if you are using CyberPanel you can easily see disk space usage on your dashboard after your login.

 

We recommend CyberPanel for self-managed VPS as well, because it helps you to manage most of the things within few minutes, otherwise you could be spending lots of time doing the same thing. You can start using CyberPanel for free with just one install command, for more details visit the installation page.


Why you see Disk Quota Exceeded error?

 

If you are a website owner, and running a managed or self-managed VPS. There are 99% chances that you must have configured some sorts of backups and logging as well (logs generated by different application, to debug any issue in case something funny happens later). So there are some example of files that could be using extensive disk space and you don’t know about them:

 

  • Large old backup files residing on the server that you have not deleted.
  • Large log files from web server or any other applications that you have not deleted after they are rotated by the application.
  • Some un-used applications or staging setups that you did during developent.
  • Spam or deleted mail folders still containing large amount of emails that you don’t know off.

 

All these files could occpuy large amount of space ending up causing disk quota exceeded error.


Lets first find out large directories and files

 

We will first try to find out large files and directies in your server, you can then decide if those files  are safe to be deleted, ending up giving you more space.

 

cd /home

du -hs * | sort -rh | head -20

 

These command will print out large files and directories under /home directory of your server. You can then figure out what directories can possibly contain files that are not needed. Similary you can run this command under various directories such as /var/log

 

Make sure you don’t something which is important, and if you don’t know what you are doing, then it is better you let our experts do the work by hiring our managed vps or monthly support package we offer 3 days free trial (no credit card required).

 

If using CyberPanel

 

As mentioned above we recommend CyberPanel for managing your day to day server tasks, so if you have already  decided to use CyberPanel. Look for following directories as they must be containg large backup files that you won’t need.

 

/home/domain.com/backup

/home/backup

/usr/local/lsws/logs


Exceeded number of inodes (file entries) supported by your choosen file system

 

There is a possibility that you still have enough disk space left, but you reached inodes limit end up giving disk quota exceeded. First make sure you that you have enough space left.

 

Filesystem Size Used Avail Use% Mounted on
/dev/vda1 25G 6.9G 19G 28% /

 

You can see that disk space is only 28% used. Now check if you reached inodes limit.

 

df -i

Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/vzfs 2000000 2000000 0 100% /

Now this means you have reached 100% of your inode usage. It is time that you delete smaller files that are no use to your applications. For example find large number of small files under /var

 

find /var -type d -size +256k

 

Similaly you can find small files under /home as well, and delete files to resolve disk quota exceeded error. Some type of files that you can easily delete are:

 

  1. Cache files generated by servers (LiteSpeed Server use disk for cache). Incase of LiteSpeed cache folder is created under home of each user.
  2. Sessions files generated under /tmp and not being deleted.
  3. Catch all email inbox may have 1000s of emails you don’t need to keep, so they can be easily discarded.

 


Easy way to clear some space if you are using CyberPanel

 

As adviced by us, if you are now using CyberPanel, there are some easy way to free up disk space safely.

 

Remove OpenLiteSpeed Cache folder

 

rm -rf /usr/local/lsws/cachedata

 

Remove Cache folders when using LiteSpeed Enterprise

 

rm -rf /home/domain.com/lscache

 

You can do this for every domain. (By replacing domain.com with your domain)

 

Delete Backups

 

rm -rf /home/domain.com/backup/*.tar.gz

 

You can do this for every domain. (By replacing domain.com with your domain)

 

You can also do

 

rm -rf /home/backup/*

 

Remove old CyberPanel versions

 

rm -rf /usr/local/*.tar.gz


Conclusion

 

We’ve discussed many reasons and their fixes related to disk quota exceeded error.  If you are still stuck at some point and don’t have much time or expertise to fix this issue, you can contact us to get help.

 

Sometimes it may just be a limitation imposed by any control panel you are using, and you could be losing important business emails due to this. So while you are fixing and debugging the cause, it is better to increase disk limit size for your accounts or mailboxes, so that you won’t lose important stuff.

 

How to resolve “localhost connection refused”?

When on windows you usually use putty to connect to remote SSH servers or terminal when on Linux. While connecting sometimes you can get error such as localhost connection refused on putty or your Linux terminal. Now, this can be very annoying as you can’t get to SSH of your remote server and perform your tasks.

 

This problem can be from the server or client-side. In this tutorial, we will see probable causes of this error and how to fix them. If you are using our managed vps, then you just have to contact us via ticket or live chat and we should fix this for you.

 

Let’s continue and see reasons for this error and how to resolve localhost connection refused.


Possible error messages on Putty or Linux Terminal

 

We will first see possible error messages that you will see.

 

In putty

 

Putty Fatal Error
Network Error: Connection Refused

On Linux Terminal

 

ssh: connect to host 51.xx.xx.xx port 22: Connection timed out

 

Now the connection to the server is properly routed, but the server is not accepting your connection for many reasons that we will discuss below.


Reasons and Fixes for localhost connection refused

 

We will now discuss reasons and fixes for this error one by one.

 

1. SSHD Daemon not running

 

It is possible that SSHD daemon on your remote server is not running. For SSH to work there is a daemon that works behind the scene and it is called SSHD. If this daemon is not running your server will not be able to accept SSH incoming connections. Check if this service is running or not:

systemctl status sshd

If it is not running you can turn it on:

systemctl start sshd

 

SSHD does not start?

Now for some reasons if your SSHD daemon still won’t start make sure you have enough disk space using:

 

df -h

 

If you have enough space you can see if your server is receiving heavy traffic or if the server is under heavy load. You can hire our managed vps service as well we offer 3 days free trial (no credit card required)

 

2. Firewall blocking SSH Port

 

Most of the time there is some firewall blocking the SSH port. First, see if you can telnet to SSH port 22

 

telnet 192.xx.xx.xx 22

 

Then check if you or user IP is blocked on IP Tables firewall

 

iptables -nL

 

If IP is listed, you need to unblock this IP to restore connectivity to SSH port 22. There is also a possibility that firewall has dropped or reject rule for SSH port 22, you need to remove that rule and add run following command:

 

iptables -A input -p tcp –dport 22 -j ACCEPT

 

If using CyberPanel

 

If you are using CyberPanel it comes with Firewalld by default unless you have installed CSF. You can go to :8090/firewall/ by default port 22 is opened, if not you can add port 22 there.

 

If you have installed CSF with CyberPanel, you can use csf.allow file to allow this IP. The file is located at

 

nano /etc/csf/csf.allow

 

Then turn off and turn on CSF again from CyberPanel interface.

 

3. Custom SSH Port

 

If you have defined a custom port for SSH (for security reasons, because standard SSH ports are prone to brute force attacks). Then you need to open that port on the firewall as well. Because firewall doesn’t know you choose a custom port for SSH.

 

First, confirm if you are using custom port using

 

cat /etc/sshd_sshd_config | grep Port

 

If you see something other then port 22, you need to fix it.

 

iptables -A input -p tcp –dport custom_port_here -j ACCEPT

 

Replace with custom port here.

 

If using CyberPanel

 

Go here :8090/firewall/secureSSH and see if you have set custom ssh port. Normally if you set custom SSH port, CyberPanel will open this port for you on the firewall. But if it still does not work, you can open this port manually by going to :8090/firewall/ or here :8090/firewall/csf if you are using CSF.

 

4. Incorrect IP, SSH Port or Key File

 

It is also possible that you did a human error and used incorrect IP or wrong SSH port. Make sure you are using right IP on putty or Linux terminal along with correct SSH port.

 

Sometimes people also use key-based authentication, and they get issues while connecting to SSH if the wrong private key is used or there are wrong permissions on your SSH private key. On your local server make sure that your private key has the permission of 600.


Why use CyberPanel?

 

We’ve discussed many reasons and fixes for localhost connection refused error. But we recommend that you install CyberPanel on your VPS, it will help you solve many issues and if you are hosting sites then you will get super speed as well because CyberPanel is based on OpenLiteSpeed and LiteSpeed Enterprise.

 

You will get easy access to Firewalld (installed by default) where you can easily open/close any ports at your wish. Or you can also install CSF too.

 

If you are very novice user you can also hire our managed vps service, we are super affordable and provide top-notch support to all our customers. You can start with 3 days trial (no credit card required at all).

FTP 550 No such file or directory

FTP (File Transfer Protocol) is a standard network protocol used to transfer files between clients and servers. It is the fastest way to upload your file on the server. If you are using CyberPanel, you can also use File manager, but it is always recommended to use FTP to transfer large files to your server. However, as with any other software people face an issue with FTP as well. In this tutorial will discuss one FTP error called ‘FTP 550 No such file or directory’. This means file or folder does not exist.  Today will see what are the main reasons behind this error and how to fix them.

 

However, if you are our customer and use our managed vps service, feel free to contact us via helpdesk to get this issue resolved.

 

What is FTP 550 No Such File or directory

 

We will first see what actually is FTP 550 No Such File or directory error.

 

5xx errors with FTP means complete rejection from the server. Which means that your FTP client such as Filezilla sent an FTP command which remote server fails to accept and returns with 5xx families of error.

 

It is also related to File system issues, for example, the FTP users do not have access to the folder you are trying to access or upload content too.

 

What is the main cause of this error

 

1. Wrong Permissions 

 

If your folder or files have wrong permissions this will also cause ‘FTP 550 No such file or directory’. This happens when the user does not have enough privileges to edit or open file they are trying to access. So if you are using CyberPanel avoid uploading files via root SFTP account, because those files will then be owned by root account and you can then can’t access those files via FTP.

 

If you have already done so, make sure to click Fix Permissions from the file manager. Or you can log in to ssh via root, then first find out the user of your website by running:

 

ls -la /home

 

This command will tell you the owner of the directory who owns your document root, you can then run following commands to change owners of your document root

 

chown -R user:user /home/domain.com

 

Also, this status code occurs when you try to GET a file that does not exist.

2. Incorrect Path 

 

FTP 550 No such file or directory can also occur if you are trying to upload file to an incorrect path.  Such as if the file is present in the document root of your site at /home/domain.com/public_html and you are trying to upload from /home.

 

The easiest way to get around the incorrect path is to logout from FTP, and log in again. You will then land in the default FTP folder and from there you can easily navigate to the folder you want to upload file to.

 

3. Wrong Mount Point 

 

Sometimes users mounts filesystem at a certain mount point but they don’t configure it to retain after reboot. So after server reboot that mount point does not exist anymore. In such case when they login to that FTP account they usually see 500: No such file or directory, because that mount point does not exist anymore.

 

Make sure to remount the file system and make it persists during the reboots.

 


How to Create FTP Account In Cloud Platform

 

 

Once the website is created, click on your service ID. You will be brought back to the page where you can manage your sites created in the CyberPanel.

 

 

Click the launch icon.

 

 

From the left sidebar, click Create FTP Account under FTP. Fill in all the details and click Create FTP button. You can leave the path empty and default path will be used which is usually document root of the website (i.e. /home/domain.com). But if you set some path such as helloworld the final path will be relative to document root such as /home/domain.com/public_html/helloworld.

 

FTP Account is necessary to upload your website/application files. But if you are going to use our Auto Installer creating FTP account is not really necessary.

 

You can also use default File Manager of CyberPanel to manage files of your website, but for large uploads, FTP is recommended.