I use X Forwarging over SSH for several things to manage, such as virtual machines with “virt-manager”. Today, when I wanted to run a graphical tool on one of the servers I kept getting this error. Error: Can’t open display: localhost:10.0 I verified all the possible configurations issued, launched the ssh command with -v argument […]
When your maillog on a CentOS/*EL machine looks like this: mail postfix/smtpd[19345]: connect from unknown[XXX.YYY.ZZZ.QQQ]
Well, on a high-traffic mail server we need to follow the server log, to look for possible issues. The “tail -f” method might just not be as good as we would want, text is going up too fast and web just can’t read that fast. A solution to that is multitail. On CentOS/RHEL we would […]
Let’s say you’re on a news website for instance bbc.co.uk, that you read a lot, but each time you look on the website you can’t tell if you already visited that portion of the website or not. Let’s say you still have a chance, there’s a Firefox and Chrome add-on called Stylish. First you need […]
Even if you’re running on a tiny VPS or on a huge server when you have a LAMP stack your biggest memory consumer will probably be MySQL. Some even prefer running it on a different machine when it comes to high traffic web apps. But, as your apps are put to work MySQL tends to […]
Asuming we have on a mail server(that hosts domain1.com) some external aliases, like user1@domain1.com has an alias for user1@domain2.com, which is hosted on a different server, probably on a different mail provider. Typically when a mail is sent to user1@domain1.com, it’s sender’s mail server sends the mail to the MX which hosts domain1.com the mail […]
Because Debian Linux distro has it’s way of testing packages before they end up in the stable version, these packages might be sometimes outdated or you just wand to benefit from the newest functionalities for some packages. Debian Backports is a repository that you can use for these cases. In order to use the repository […]
To be honest I use OpenVPN quite rarely on my Android tablet, and it happens only when I need to access certain locations that tie me to a certain IP address. This type of connection could be more often used when the tabled would serve as an email reading device at a company that would […]
When you manage Postfix mail servers using SQL connections to find informations about usernames, mailbox/maildir locations on the disk you probably have in your main.cf something like : virtual_alias_maps = mysql:/etc/postfix/mysql_virtual_alias_maps.cf virtual_mailbox_domains = mysql:/etc/postfix/mysql_virtual_domains_maps.cf virtual_mailbox_maps = mysql:/etc/postfix/mysql_virtual_mailbox_maps.cf relay_domains = mysql:/etc/postfix/mysql_relay_domains_maps.cf But, this way, each process(postfix process) uses one MySQL connection. Each mail that relays thru […]
On a Debian or Ubuntu system, we need to make sure that when a new user is created it’s files are not generally available for reading to other non-root users. By default home folders are created with 0755 permissions (readable by everyone). To change this we just need to adjust a parameter in the /etc/adduser.conf […]