The ~/.ssh/config file don’t have a directive for including other files, possibly related to SSH’s check for file permissions. Suggestions around this can include a script to cat several changes together either on the system or via checkin hooks on a repository. One might also look into tools such as Puppet or Augeas. However you … Read more
David’s answer is a good baseline of the general principles of server hardening. As David indicated, this is a huge question. The specific techniques you take could depend highly on your environment and how your server will be used. Warning, this can take a lot of work in a test environment to build out and … Read more
Edit /etc/default/locale and set the contents to: LANG=”nl_NL.UTF-8″ You can check which locales you currently have generated using: locale -a You can generate more by editing /etc/locale.gen and uncommenting the lines for the locales that you want to enable. Then you can generate them by running the command: locale-gen You can find a list of … Read more
The commands dig and host should be what you’re looking for 😉 On *nix systems, you can use this command: dig -x [address] Alternatively, you can add +short at the end of the dig command to output only the DNS result. There’s also nslookup on both *nix and Windows systems for reverse DNS requests.
Edit for 2016: This Q&A predates the systemd v230 debacle. As of systemd v230, the new default is to kill all children of a terminating login session, regardless of what historically valid precautions were taken to prevent this. The behavior can be changed by setting KillUserProcesses=no in /etc/systemd/logind.conf, or circumvented using the systemd-specific mechanisms for … Read more
sed -n ‘10000000,10000020p’ filename You might be able to speed that up a little like this: sed -n ‘10000000,10000020p; 10000021q’ filename In those commands, the option -n causes sed to “suppress automatic printing of pattern space”. The p command “print[s] the current pattern space” and the q command “Immediately quit[s] the sed script without processing … Read more
What can be simpler than echo $!? As one line: myCommand & echo $!
You can do it by using this simple one way command, which uses the /proc/modules and /sys virtual filesystems: cat /proc/modules | cut -f 1 -d ” ” | while read module; do \ echo “Module: $module”; \ if [ -d “/sys/module/$module/parameters” ]; then \ ls /sys/module/$module/parameters/ | while read parameter; do \ echo -n … Read more
Unfortunately this in now a very common occurrence. It is an automated attack on SSH which is using ‘common’ usernames to try and break into your system. The message means exactly what it says, it does not mean that you have been hacked, just that someone tried.
For those who don’t have an account on the forums (or don’t wish to login): if your main issue is not to ping but to ssh, you can create/edit your ~/.ssh/config adding lines like these: Host fakehost1 Hostname real-hostname Host fakehost2 Hostname real-hostname2 Host fakehost3 Hostname real-hostname3