Category: linux

SCHEDULED CHRON TASKS

Linux has the ability to run a shell script whenever desired. We use one to automatically install updates and if necessary reboot the system. sudo apt-get needrestart adding this program makes it easier to test for reboot required due to a kernel update etc. needrestart -k will reboot if the system is prompting for a …

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HTTP 301 REDIRECT

Ordinarily when a web site URL changes HTTP 301 permanent redirect is used tell a search engine where to look, HTTP 404 errors can be categorically sent to the home page. There is a full search capability with any SQL driven system and WordPress supports it with all themes. Given some URL errors we estimate …

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WEBMIN

Unfortunately Ubuntu liNUX does not offer web based administration directly, instead users have to manually add the Debian repository. This is inconvenient and its a fair amount of work involved to add this to the system. Now you need to install webmin from APT repository sudo gedit /etc/apt/sources.list then add to the bottom deb http://download.webmin.com/download/repository/ sarge …

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FREEBSD

Originally Unix was owned by AT&T and BSD was based on the source code from this time. When AT&T spun off Bell Labs it was freed from being required to license Unix for free. In 1984 Bell Labs wanted license feeds for Unix. This did not go over well and open source quickly moved to …

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OPENSSL 1.1.0.b

Another vulnerability has been discovered and patched for OpenSSL https://www.openssl.org/news/secadv/20160926.txt For LAMP users there is also a new version of MySQL available, it updated our server without problem sudo apt update sudo apt full-upgrade reboot your server to be sure the stack is clean sudo reboot  

LINUX PASSWORDS

Generally all distributions of Linux have used cryptographic hashes for passwords for a very long time. A salt was added when rainbow attacks were in vogue in the early 2000s. Windows is behind the curve: they still do not salt passwords. WIndows is limited to 16 symbols for passwords. salted_pass = password + salt; hash …

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NETWORK TIME

Generally a Linux virtual machine can get the date and time from the hypervisor but the overhead of adding network time is minimal. sudo apt-get install ntp by default this will have some default servers already configured so there is no need to add more linux can automatically calculate the drift from the official time …

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APACHE & HTTPS

Starting in January 2017, Google Chrome will start flagging web sites which do not use HTTPS. At present about 50% of web sites use HTTPS. Google is aware of incremental cost of a web site obtaining a certificate etc. This means its likely that page ranks of non-HTTPS sites will be reduced severely. The net …

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SETUP VSFTPD FOR LINUX ON AZURE

Ubuntu Linux virtual machines have FTP available however that does not provide remote file transfer, WinSCP or Filezilla can handle the Windows client requirements. Remember to open the FPT port 21 in the Azure firewall. There is a preset for FTP on Azure which is all you need. Azure also by default already has the …

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SECURITY FOR LINUX SERVER

UNDER CONSTRUCTION Linux was for many years ignored by miscreants who prefered to attack Windows machines. Today however servers are under attack from all angles. The first too to install is to guard against rootkit type attacks. These are troublesome as they can hijack a server outright. sudo apt-get install chkrootkit