Multidomain webroot for Letsencrypt with NGINX

If you have web server on which there is a lot of virtual hosts, you may want to have one webroot directory for Letsencrypt SSL certificates only. So when Letsencrypt will make the requests for SSL registration or renewal, it will look in this directory. In this case I did this on CentOS 7 with NGINX web server.

First, let’s create directory what will be used for letsencrypt purposes. It must be writable by your web server user. You can define different path.

[root@machine ~]# mkdir -p /var/www/le-certs
[root@machine ~]# chown -R wwwuser:wwwgroup /var/www/le-certs

Letsencrypt will need access in “.well-known/acme-challenge”. For NGINX add something like this in your server block for desired virtual host.

location ~ /.well-known/acme-challenge/ {
             root /var/www/le-certs/;

You can also create new file named, for example le-config.conf and add block above in to it. Then you can simply include this line in your virtual hosts. 

server {
             listen :443 ssl http2;
             root /var/www/mywebsite/;

             include le-config.conf;



Pure-FTPd: install valid SSL certificate / solve untrusted localhost certificate problem on CentOS 7

If you installed Pure-FTPD on your CentOS 7 machine and trying to install SSL certificate on it, chances are that you added your pem file to “/etc/ssl/private/”. I installed valid certificate in this directory and still getting untrusted warning for localhost certificate. Later, I found out that this path is wrong and self signed certificate was being used. Right path on CentOS 7 is “/etc/pki/pure-ftpd/”.

Here is how to do it right on Centos.

  • Create pem certificate that contains your key, crt and intermediate all in one file – pure-ftpd.pem
  • Move this certificate to /etc/pki/pure-ftpd/ as this is the right directory on CentOS.
  • In your pure-ftpd.conf, set TLS to 2.
  • Enable PassivePortRange from 30000 – 65000.
  • Restart pure-ftpd.

It should work.

SFTP: Command failed

If you try to connect via SFTP with some FTP/SFTP client and you are getting error “Command failed”, you’re sftp-server path in sshd_conf is wrong.

Open your sshd_config file and edit sftp-server path accordingly to your OS.


Subsystem sftp  /usr/lib/openssh/sftp-server


Subsystem sftp /usr/libexec/openssh/sftp-server

Restart your ssh and it should work.

Linux: restore all system permissions of your server

If you ever found your self in situation when you accidentally overwrite all permissions of your system, and everything stops working, then solution bellow may do the trick. This CentOS server was overwritten by wrong permissions through the whole system. Quick solution is to set up right permissions back. If you have backup of server that’s great. Otherwise you’ll have to set up new server with similar installation or do this on some other server with similar installation.

On “new” server, copy permissions of the whole system and save it to a file. You can also exclude dirs that you don’t need also.

find / -not -path "/proc*" -not -path "/dev*" -not -path "/sys*" -not -path "/var/www*" -exec stat -c "chmod %a %n;" {} \; > permissions.txt

On your “broken” server, rewrite all permissions:

cat permissions.txt | bash

YUM: Error: Network error: Connection reset by peer

If you get this error message when trying to install packages via yum package manager, than just execute command bellow and it should fix your problem.

yum clean expire-cache

Update all php extensions at once with YUM

With YUM, upgrading php is simple as “yum install php”. This will install latest php version on your machine. But if you have multi different php modules that aren’t part of php package (eg. gd, mysqli …), than you can use this simple one liner and install all those modules at once.

Just run this as root:

php -m | grep -v "Modules" | while read i; do yum install php-$i -y; done

This will check for all currently installed php packages and will try to upgrade them.

Directadmin/Letsencrypt – Domain does not exist on the system. Unable to find in /etc/virtual/domainowners

A few days ago I was doing complete migration of old Directadmin server to new Directadmin server which had different hostname. Everything went well but I was unable to register Letsencrypt SSL certificate for new server hostname.

I was getting error like this:

[root@myserver scripts]# ./ request 4096
Domain does not exist on the system. Unable to find in /etc/virtual/domainowners. Exiting...
no valid domain found - exiting

First thing I did is I add new hostname as domain to user admin. Certificate was indeed registered than, but not as server hostname (/usr/local/directadmin/conf/cacert.pem). I deleted domain than.

After a little search I found out that I forgot to change servername variable in directadmin.conf. So I changed it, restart directadmin but I was getting the same error. At the end I found out that the easiest way to fix this is to change hostname in Directadmin administration.

  1. Go to Directadmin as admin user and navigate to Administrator Settings, then set some temporary hostname in Server’s Hostname. Let’s say
  2. Wait until cron will make changes – you should see new hostname in Administrator Settings when refreshing page.
  3. Go in Administrator Settings again and change Server’s Hostname to your old hostname –
  4. Run again.

This time, certificate was registered successfully.

[root@myserver scripts]# ./ request 4096
Setting up certificate for a hostname:
Generating 4096 bit RSA key for let's encrypt account...
openssl genrsa 4096 > "/usr/local/directadmin/conf/letsencrypt.key"
Generating RSA private key, 4096 bit long modulus

fail2ban – Error in FilterPyinotify callback: illegal IP address string passed to inet_aton

Just recently, I discovered great pice of software named fail2ban. Supreme way to provide some additional security to your server. But more about fail2ban next time. So, I configured my jail.local configuration, but getting errors in error log. This was the error:

Error in FilterPyinotify callback: illegal IP address string passed to inet_aton

Error is pretty self explanatory, my whitelisted IP’s defined in variable ignoreip were wrong. If you use commas (,) like I did, then there is your problem. Just replace commas with spaces and it should work fine.

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