Kyle Pericak

Created: 2020-10-20, Modified: 2020-10-20

Fixing ERR_CERT_COMMON_NAME_INVALID by generating an openssl CSR with Subject Alternative Names, using a reusable san.ini config file and openssl req.

Created: 2020-07-23, Modified: 2020-07-23

Click-by-click steps for adding an 802.1Q VLAN tag to a Thunderbolt Ethernet adapter on macOS so you can plug a MacBook into a switch's trunk port for testing.

Created: 2020-06-05, Modified: 2020-06-05

Create a Windows KVM virtual machine on Ubuntu 18.04 from the command line with qemu-kvm, libvirt, virt-install, and a netplan bridge. No OpenStack required.

Created: 2020-06-04, Modified: 2020-06-04

Quick reference for capturing and filtering network traffic on Ubuntu using tcpdump and tshark. Covers port filters, host filters, combined expressions, and tshark HTTP capture.

Created: 2020-03-09, Modified: 2020-03-09

Install and configure an NFS server on Ubuntu 18.04 with nfs-kernel-server, set up /etc/exports for a subnet, apply with exportfs, and mount from a client.

Created: 2020-03-06, Modified: 2020-01-13

Push a one-off file to a locked-down Windows box from Linux by hosting it with `python -m SimpleHTTPServer` and grabbing it in Internet Explorer.

Created: 2020-01-13, Modified: 2020-01-13

Install LetsEncrypt's certbot on Ubuntu and issue a free HTTPS certificate using the standalone HTTP challenge, then convert the files for HAProxy use.

Created: 2020-01-08, Modified: 2020-01-08

Extract a corporate CA certificate with openssl s_client and install it on Ubuntu via /usr/local/share/ca-certificates and update-ca-certificates.

Created: 2019-12-16, Modified: 2019-12-16

Restoring a USB drive's full size on macOS after dd or Etcher shrank it for a boot disk, using diskutil eraseDisk and, if needed, zeroing the partition with dd.

Created: 2019-09-17, Modified: 2019-09-17

Build a persistent reverse SSH tunnel from an Ubuntu box at a customer site to your own pivot VPS, so you can remote in without a VPN.

Created: 2019-08-20, Modified: 2019-08-20

Configure a Sender Policy Framework DNS record so mail servers trust emails from your domain. Covers finding your external IP and setting the TXT record.

Created: 2019-08-20, Modified: 2019-08-20

Turn an Ubuntu Server into a WiFi-to-wired NAT gateway using netplan, IP forwarding, and iptables MASQUERADE so switched servers can reach the internet.

Created: 2019-08-19, Modified: 2020-03-09

Connect Ubuntu Server 18.04 to a WPA2 WiFi network from the command line using wpa_supplicant, iwlist, and netplan, including offline package install steps.

Created: 2019-08-19, Modified: 2019-08-19

Run Chrome on a headless Ubuntu server and render it on a Mac with SSH X11 forwarding, XQuartz, and ssh_config tweaks. No VNC, RDP, or desktop install.

Created: 2019-08-18, Modified: 2019-08-18

Write a cron-driven bash script that pings a host every minute and sends a throttled email alert on failure, using the mail command and a token file.

Created: 2019-08-15, Modified: 2019-08-15

Install and configure Postfix on Ubuntu as a local send-only SMTP server for alert emails, including hostname setup, main.cf tuning, and the mailutils tools.

Created: 2019-08-8, Modified: 2019-08-8

Transfer a domain from GoDaddy to Cloudflare for faster DNS propagation and cheaper registration. Covers unlocking, auth codes, and finalizing the move.