Articles in the System Administration category

  1. OpenSSH: Using a Bastion Host

    Quick and dirty OpenSSH configlet here. If you have a set of hosts or devices that require you to first jump through a bastion host, the following will allow you to run a single ssh command:

    Host *
        ProxyCommand ssh -A <bastion_host> nc %h %p
    

    Change the Host * line to …

  2. Cache has broken packages, exiting

    I've been getting the following error from cron.daily in my inbox lately:

    /etc/cron.daily/apt:
    Cache has broken packages, exiting
    

    That's an annoying email to get everyday. I decided I would apt-get clean and that would probably fix the problem:

    $ sudo apt-get clean
    $ sudo apt-get dist-upgrade
    Reading package …
  3. MySQL OOM'ed, But Pelican Lives

    Pelican logo -left I use Pingdom's free service to monitor slaptijack.com. Apparently, late Friday night, oom-killer decided that the server needed more memory and took out the MySQL server. To make matters worse, I missed the alarm from Pingdom, and slaptijack.com was down for pretty much all of Saturday. The fact …

  4. Removing a Single Line from known_hosts With sed

    OpenSSH logo Ever so often, something changes on the network, and you find that your .ssh/known_hosts file has gotten out of date. Usually this happens after an upgrade or device change. You'll get the rather ominous warning that REMOTE HOST IDENTIFICATION HAS CHANGED!

    If you are confident that someone isn't …

  5. Bypass RBL Check in Exim

    Exim logo -left Although I do not use Exim myself, I have clients that do. Recently, we noticed that it was taking more than 20 seconds for their SMTP banner to display when initiating checks from the monitoring server. Connecting to the server locally (on any interface IP address) did not suffer the …

  6. Enable gzip in Nginx

    nginx logo -leftIf you have ever used any tool to optimize a web page, you know that compressing the return traffic to the client is a big win. In nginx, this is done with the gzip module. The easiest thing to do is add gzip on; to the http stanza in your …

  7. Magento Home Page Returns 404 Status Code

    Magento logo -leftNaturally, I ran into this problem in the middle of the night when the client was asleep and I had no access to the Magento administrative interface. The short story is that after running a re-index of the site, the home page began returning a 404 error status. A bit …

  8. MacPorts: upgrade gnutls failed

    MacPorts logo I ran into this issue while trying to install wine-devel on my Mid 2012 MacBook Pro running El Capitan and MacPorts 2.3.4. As the install progressed, here is the error I got:

    Error: org.macports.build for port glib2 returned: command execution failed
    Please see the log file …

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