Create and password protect/encrypt zip archive from command line / stored 0% message

When sending zip archives that contains risky/secure content, you should always encrypt and password protect them. Especially when sending them to clients via email, Dropbox or some other public sharing method. To do that on Linux is very simple. You can do it with commands bellow. When executed you’ll be prompted to enter password.

When adding file, just do this:

zip --encrypt myarchive.zip myfile.txt

But when adding directory with subdirectorys and files, than you should always include “-r” flag to tell zip to use recursion. Otherwise you’ll end up with empty directory and see message like this “adding: behaviour.exchange/ (stored 0%)”

To add directory recursively:

zip --encrypt -r myarchive.zip mydir/

 

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 your.hostname.com 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]# ./letsencrypt.sh request my.server.com 4096
Domain does not exist on the system. Unable to find my.server.com 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 my.server2.com.
  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 – my.server.com.
  4. Run letsencrypt.sh again.

This time, certificate was registered successfully.

[root@myserver scripts]# ./letsencrypt.sh request my.server.com 4096
Setting up certificate for a hostname: my.server.com
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
...

malware acl condition: clamd: unable to send file body to socket (127.0.0.1)

If you see error like this in your mail logs, than chances are that your ClamAV is not able to process attachments files larger than limit set in clamav configuration. In this case, sender which sent email with larger attachment to your server, will get something like this in respond:

[10.10.10.10] #<[10.10.10.10] #5.0.0 smtp; 5.4.7 - Delivery expired (message too old) [Default] 451-'Temporary local problem - please try later' (delivery attempts: 75)> #SMTP#

In your mail log you’ll see something like this:

+++ 1e248B-000NMy-T6 has not completed +++
1969-08-15 01:40:21 1e248B-000NMy-T6 malware acl condition: clamd : unable to send file body to socket (127.0.0.1)
1969-08-25 01:40:21 1e248B-000NMy-T6 H=some.hostname.com [1.1.1.1] X=TLSv1:RC4-SHA:128 CV=no F=<prvs=449d2f142=senders@email.com> temporarily rejected after DATA

To solve this, open your clamav.conf file (/etc/clamav.conf or find your location) and change value for StreamMaxLength according to your needs. Default value is 25M.

Don’t forget to restart your ClamAV.

Directadmin – install Letsencrypt SSL certificate on server hostname

Letsencrypt is a revolutionary step forward on web security. Free, valid SSL certificates for everyone. I won’t write about how to install and config letsencrypt on Directadmin machine. I will show only how to generate and install letsencrypt certificate on your Directadmin hostname.

When you installed Letsencrypt on Directadmin and tried to install certificate for your server hostname, there is a possibility that you came to this problem: HTTP/1.1 400 Bad Request

Just do this:

cd /usr/local/directadmin/custombuild
./build update
./build letsencrypt

And than install certificate on your server hostname:

/usr/local/directadmin/scripts/letsencrypt.sh request my.serverhostname.com 4096

Open your Directadmin configuration file and change

SSL=0 to SSL=1

Also add this:

carootcert=/usr/local/directadmin/conf/carootcert.pem

Restart your Directadmin and you should be set.

Directadmin – enable and configure Spamassassin automatically on creating user

By default, when you add new user in Directadmin, Spamassassin is disabled. Some users are not aware about Spamassassin, so they’ll have it disabled and will receiving a lot of spam. It is good practice to enable Spamassassin by default and also set some settings. You can do that by adding below code in your /usr/local/directadmin/scripts/custom/user_create_post.sh script. The first step is well described on Directadmin documentation. But you may also want to define some parameters for Spamassassin when user is created. It’s really simple. You can do that by manipulating filter.conf file. Steps below are preformed on Directadmin running on FreeBSD. It should be the same for Linux also.

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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.

Find and replace whitespaces from your filename

If your files contain whitespaces in their names, it can sometimes be a real pain. Expressly if you are on Linux or Unix systems. I had some problems when running rsync for backup my files. Files with whitespace were causing problems. So bellow is simple command that will remove all whitespace and replace them with “_”. You can change to any symbol that you like. I example bellow, I was searching for all jpg files.

find . -type f -name "* *.jpg" -exec bash -c 'mv "$0" "${0// /_}"' {} \;

Scan your cPanel/Directadmin for excessive files

When dealing with cPanel/Directadmin that contains a lot of users, you need some control of what those users are uploading. Web hosting accounts should be used just for that, hosting websites, and not as data storage – in most cases. Sometimes you even offer packets with unlimited disk capacity but you don’t want that users are storing movies and all kind of other unnecessary files that don’t belong on web hosting account. From web hosting perspective, in most cases, any single file that exceeds 100M is usually not part of website and is just laying there, wasting your precious disk space. In cases like this, account is used as backup service. You’ll be able to find all kind of files. Movies, music, applications, archives …

So you may want to have some reports on regular basis that gives you list of all files that exceed some maximum allowed file size limit – defined by you. Personaly, I scan on interval of 7 days for all files that exceed size of 300M. I created a simple script that will do just that. It will check your /home directory for all files that exceed size that you defined. At the end, report will be sent to your email. You can also scan other directory beside /home if you wish.

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