System Administration

Out-of-Office Messages are a Security Risk

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Every once in a while I get asked why I don’t have an out-of-office message for my email or voice mail. Truth is, I’ll often monitor my email even when I’m out, though I often practice good operations discipline by not responding. Just as intermittent problems with computer systems are hard to deal with, a staff member that’s supposed to be gone but isn’t acting like it is just as confusing. Humans can, and should, drain-stop and remove themselves from clusters for maintenance, too. Sometimes I’m really out of the office, though, crawling around in the backcountry wilderness or on an island somewhere. I’ll do it if I have to, but even then I don’t like setting an automatic response. …

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Free, Like a Puppy

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I’ve found that things that are free of charge are often not a good deal. TANSTAAFL, or “There ain’t no such thing as a free lunch.” You’re always paying in some way. Maybe the piece of hardware is marked up more to cover the development cost of the “free” software that comes with it. Perhaps it’s the drug dealer model, where the first one is free to get you hooked. Sometimes you’re the product, and the “free” thing is spying on you with the hopes of making more money from ads or sales later. Certainly nearly every “free” web service is structured that way. Beyond monetary cost, though, you paying for things with your time. “Free” things often fall into …

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Retrieve an SSL Certificate from a Server With OpenSSL

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I was setting up VMware vRealize Automation’s Active Directory connections the other day and I needed the public SSL certificate for the AD DCs to authenticate correctly. You can use OpenSSL to get that information. I used a Linux shell but this should be do-able from a Mac or with OpenSSL installed on Windows, too. If you wanted to read the SSL certificates off this blog you could issue the following command, all on one line: openssl s_client -showcerts -servername lonesysadmin.net -connect lonesysadmin.net:443 < /dev/null In this case you’ll get a whole bunch of stuff back: CONNECTED(00000003)depth=2 O = Digital Signature Trust Co., CN = DST Root CA X3verify return:1depth=1 C = US, O = Let’s Encrypt, CN = Let’s …

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CODE Keyboard

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“You spent $150 on a keyboard?” – My wife There are two kinds of people in technology: those with an opinion about their keyboard, and everybody else. I happen to be one of the first. I grew up using the IBM Model F and M keyboards. They have a spring in the key switches that buckles as you press down. That gives you two things: a prominent clicking sound from the keypress, and solid tactile feedback from the key. You definitely know when that key switch actuated. Years ago I had to give up my Model M keyboards. They’re built to last but it was getting harder to find working ones, it was getting inconvenient to adapt them to USB …

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Fixing X11 Forwarding Over SSH and with Sudo

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X11 forwarding over SSH not working? Not setting $DISPLAY correctly in your shell? Having problems with X11 and sudo? Yeah, me too. Total pain in the duff. Here’s what I do to fix it. I’m thinking about Linux when I write stuff like this but a lot of this has worked on AIX and Solaris, too. Make sure your SSH client supports X11 Forwarding and that it’s turned on. I use SecureCRT but I know it works in PuTTY as well. Once you turn it on in your client & save the settings you will need to reconnect, the forwarding is established with the connection. Ensure xauth and xterm are installed. You need xauth for this to work, and xterm …

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Midnight is a Confusing Choice for Scheduling

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Midnight is a poor choice for scheduling anything. Midnight belongs to tomorrow. It’s 0000 on the clock, which is the beginning of the next day. That’s not how humans think, though, because tomorrow is after we wake up! A great example is a statement like “proposals are due by midnight on April 15.” What you actually said: proposals aren’t welcome after April 14. What you probably meant: you want the proposals before the date is April 16. There’s a 24 hour difference there, and if you enforce the deadline accurately people are going to complain because they were all thinking the second thing (before April 16). Similarly, this is a problem in change notices and customer communications. When you say …

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No VMware NSX Hardware Gateway Support for Cisco

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I find it interesting, as I’m taking my first real steps into the world of VMware NSX, that there is no Cisco equipment supported as a VMware NSX hardware gateway (VTEP). According to the HCL on March 13th, 2018 there is a complete lack of “Cisco” in the “Partner” category: I wonder how that works out for Cisco UCS customers. As I continue to remind vendors, virtualization environments cannot virtualize everything. There are still dependencies on things like DNS, DHCP, NTP, and AD that need a few physical servers. There will also always be a few hosts that can’t be virtualized because of vendor requirements, politics, and/or fear. Any solution for a virtual environment needs to help take care of those …

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How to Troubleshoot Unreliable or Malfunctioning Hardware

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My post on Intel X710 NICs being awful has triggered a lot of emotion and commentary from my readers. One of the common questions has been: so I have X710 NICs, what do I do? How do I troubleshoot hardware that isn’t working right? 1. Document how to reproduce the problem and its severity. Is it a management annoyance or does it cause outages & downtime? Is there a reasonable expectation that what you’re trying to do should work the way you expect? That might seem like an odd question, but sometimes other people do the procurement for (and without) us and there are gotchas they didn’t think to ask about. In my case with the X710s I felt I …

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Intel X710 NICs Are Crap

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(I’m grumpy this week and I’m giving myself permission to return to my blogging roots and complain about stuff. Deal with it.) In the not so distant past we were growing a VMware cluster and ordered 17 new blade servers with X710 NICs. Bad idea. X710 NICs suck, as it turns out. Those NICs do all sorts of offloads, and the onboard processor intercepts things like CDP and LLDP packets so that the OS cannot see or participate. That’s a real problem for ESXi hosts where you want to listen for and broadcast meaningful neighbor advertisements. Under Linux you can echo a bunch of crap into the right spot in /dev and shut that off but no such luck on …

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Fix the Security Audits in vRealize Operations Manager

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(I’m grumpy this week and I’m giving myself permission to return to my blogging roots and complain about stuff. Deal with it.) Several bloggers have written about the Runecast Analyzer lately. I was crazy bored in a meeting the other day so instead of stabbing myself with my pen to see if I still feel things I decided to go check out their website. My interest piqued when I saw the screen shot where they show security hardening guideline compliance, as well as compliance with the DISA STIG for ESX 6. I do a lot of that crap nowadays. You know what my first thought was about the Runecast product, though? It was “This is what vRealize Operations Manager (vROPS) could …

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