What does “error (unexpected RCODE REFUSED)” mean?

If you’re seeing this in the /var/log/syslog on your BIND DNS server: Jul 14 00:56:13 kla-dns-01 named[8255]: error (unexpected RCODE REFUSED) resolving ‘75.1.33.112.in-addr.arpa/PTR/IN’: 211.136.17.105#53 ..it means that a client has asked your server to look up a domain name that your server didn’t know about, and when it forwarded the request to it’s forwarders, the …

Continue reading ‘What does “error (unexpected RCODE REFUSED)” mean?’ »

What does “mountall: Disconnected from Plymouth” mean?

If your hard disk fills up on your Ubuntu system, you may get the following console message, and be unable to login via SSH: mountall: Disconnected from Plymouth Ubuntu 12.04.5 LTS dbserver ttyS0 dbserver login: What does it mean? Plymouth is the application which provides the graphical “splash” screen when booting and shutting down an …

Continue reading ‘What does “mountall: Disconnected from Plymouth” mean?’ »

How do I encrypt my SSH keys?

To make a new SSH key pair (private + public keys), use ssh-keygen. If you enter a passphrase, the private key file will be encrypted with that password. $ $ ssh-keygen -t rsa -f ~/.ssh/newkeyGenerating public/private rsa key pair.Enter passphrase (empty for no passphrase):Enter same passphrase again:Your identification has been saved in /Users/jsmith/.ssh/newkey.Your public key …

Continue reading ‘How do I encrypt my SSH keys?’ »

Why am I seeing “dpkg-source: not found” when I try to download source code on a Debian/Ubuntu server?

Problem I’m seeing “dpkg-source: not found” when I try to download source code on a Debian/Ubuntu server: $ apt-get source linux-headers-3.2.0-4-amd64 Reading package lists… Done Building dependency tree Reading state information… Done Picking ‘linux’ as source package instead of ‘linux-headers-3.2.0-4-amd64’ NOTICE: ‘linux’ packaging is maintained in the ‘Svn’ version control system at: svn://anonscm.debian.org/svn/kernel/dists/trunk/linux/ Need to …

Continue reading ‘Why am I seeing “dpkg-source: not found” when I try to download source code on a Debian/Ubuntu server?’ »

How do I make a Debian package?

To make a .deb package for use with Debian / Ubuntu: $ sudo apt-get install devscripts debhelper Rename the source tarball following the syntax package name_1.x.orig.tar.gz: $ mv go1.3.src.tar.gz go_1.3.orig.tar.gz Extract the tarball: $ tar xf go_1.3.orig.tar.gz Go into the source directory and create a “debian” subdirectory under it: $ cd go $ mkdir debian …

Continue reading ‘How do I make a Debian package?’ »

Why does “free” show that I have no memory free?

If ‘free’ is showing that a lot of memory is in use, even though all the processes in ‘ps’ don’t add up to all that much memory, then it might be the Linux kernel that’s using all of your memory, for caching. Ever since Linux kernel 2.2, the kernel avoids RAM fragmentation by managing it’s …

Continue reading ‘Why does “free” show that I have no memory free?’ »

How do I use the Linux find command?

The UNIX/Linux “find” command is an essential tool for UNIX administrators and users alike, and has many uses in shell scripting. Some example uses of “find” are listed below. NOTE: Unlike other UNIX commands, the paths you desire to search are specified BEFORE the program arguments. Also note that several version of “find” exist (BSD, …

Continue reading ‘How do I use the Linux find command?’ »