Linux Tutorials and Unix Similar multi-user operating systems based on the Linux kernel and essentially on GNU software. Like CentOS, Debian, Ubuntu Fedora.
How to Install Signal Desktop on Linux Mint and Ubuntu
Signal is a free messenger with encryption of the non-profit Signal Foundation. It is best known for its data economy and end-to-end encryption, and is often recommended by security experts and privacy organizations. The “zero-knowledge principle” serves as data protection, in which the provider has no access to user data.
Signal app is available for Android and iOS, a desktop version for Windows, macOS and Linux. The desktop version requires installation on a smartphone. The free signal protocol is used for encrypting messages, which security experts consider to be secure.
Signal desktop available for Linux
The Signal desktop package are available for Debian-based Distributions like Ubuntu or Linux Mint. Install from the original source signal.org repository, with perform the following commands in a terminal.
The Signal app can now be found via Start on Internet, or by entering Signal into the Cinnamon search field.
The Signal desktop app can also be provided from the application management, to do this go to Start and open the application management, enter signal in the search field in the top right corner and click on Install.
AMaViS stands for A MAil Virus Scanner and is a server-side open-source content filter for e-mails. For decoding and checking e-mails and can be considered as an interface between external content filters such as SpamAssassin, to provide protection against spam, viruses and other vulnerable malware e-mails. Amavis-new is implementet on Unixoid mail servers such as Mail Transfer Agent like Postfix.
AMaViS was written in the Unix-Shell programming language. With the further development in 2000 it was converted to Perl, from then on as amavis-new the standard interface between Mail Transfer Agents (MTA) and content filters, compatible to Postfix and interacts with the Antivirus program ClamAV and some other virus scanner. The current amavisd-new is under the GPLv2 and BSD license and also offers the possibility of integrating SpamAssassin and other filters they call Milter.
Install Amavis-new
In this tutorial we describes the installation and configuration of amavis-new. As a prerequisite, Postfix should already be available. It is assumed that Postfix is already setting up and basic skills for Postfix is well.
First step is add EPEL repository in order to install components.
We modify the following lines in the amavisd configuration. With opening in the editor of your choice. Here I use vim. if you’r not familiar with vim you can of course use nano.
$ vi /etc/amavisd/amavisd.conf
Add the changes after the comment lines.
# at line 20 set your own domain
$mydomain = 'domain.org';
# line 152 the own hostname
$myhostname = 'mail.domain.org';
# line 50 add local domain and network
@local_domains_maps = ( [".$mydomain", '.domain.org', 'next.domain.org'] ); # list of all local domains
@mynetworks = qw( 127.0.0.0/8 [::1] [FE80::]/10 [FEC0::]/10
10.0.0.0/8 10.127.99.0/24 );
# line 58 enter the exendet ports
$inet_socket_port = 10024,10026;
# line 154 w/o uncomment
$notify_method = 'smtp:[127.0.0.1]:10025';
$forward_method = 'smtp:[127.0.0.1]:10025';
# line 157 change to D_PASS
$final_virus_destiny = D_PASS;
$final_spam_destiny = D_PASS;
Now download and update the antivirus detection database.
$ freshclam
Now amavis-new configuration has been completed.
Amavis-new integrating Postfix
Let’s go ahead with the integration of Postfix. The content filter can be added at any place in the Postfix file main.cf by edit using nano or vi /etc/postfix/main.cf
content_filter=smtp-amavis:[127.0.0.1]:10024
To do this, with add the interface for amavis-new at the end of the file /etc/postfix/master.cf.
Finally you can test amavisd. Note. that during download and installing amavis-new, with the use of an UTM firewall able to detect and blocking them. The conclusion arise the download are prevented because of contains the virus test signature, because the EICAR test signature should not by capsulated.
To do this, will go to the path /usr/share/doc/amavisd-new-*/test-messages and execute the following line in terminal shell, so that the EICAR test files are decapsulated and unpacked:
$ cd /usr/share/doc/amavisd-new-*/test-messages
$ perl -pe 's/./chr(ord($&)^255)/sge'
Now send the EICAR test signature to yourself by using sendmail in a terminal shell.
If get error: reject: header To: undisclosed-recipients when trying to send the test mail with sendmail, the file sample-virus-simple.txt must be modify with a valid email entered at From: and To :.
Amavis-new Troubleshoting
To checking the functionality of amavis-new can provide along with the following procedure, first check the status of the daemon, with the parameter -l displaying the last lines of the log:
$ systemctl status postfix clamd@amavisd -l
It should also be ensured that ports 10024 and 10025 are active LISTEN: