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  • IPtables - SSH in only

    calendar Sep 6, 2022 · 1 min read · iptables linux  ·
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    I came a cross this neat little script to lock down IPtables to allow ONLY SSH in, block everything else 1#!/bin/bash 2# Flushing all rules 3iptables -F 4iptables -X 5# Setting default filter policy 6iptables -P INPUT DROP 7iptables -P OUTPUT ACCEPT 8iptables -P FORWARD DROP 9# Allow unlimited traffic on loopback …


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  • OpenSSL quick commands

    calendar Aug 26, 2022 · 1 min read · ssl linux  ·
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    Get info about a web server cert openssl s_client -showcerts -connect registry.nexgen-poc.lan:5010 </dev/null Validate a crt against a CA crt openssl verify -CAfile rootCA.crt registry.nexgen-poc.lan.crt Thanks @Deep for spotting the error!


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  • Scrub all local disks

    calendar Aug 15, 2022 · 1 min read · bash linux  ·
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    I was writing a script to scrub a server prior to decommissioning, something simple that would just make the disks unusbale enough that someone couldnt boot the OS or easily read the data. This is by no stretch a comprehensive disk wipe, if someone is lookign to recover data from these disks what were are doing here is …


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  • Use grep to view a file without comments

    calendar Aug 6, 2022 · 1 min read · bash linux  ·
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    To view the contents of a fiule but remove comments and new lines you can use this excellent little command. It will remove all lines that start with # or a new line, this is particulaly useful for viewing a config file that has 99% comments and a handful of actual values(E.G OpenStack config files) grep -v -e …


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  • PCI Passthrough error 'group x is not viable' 2

    calendar Aug 5, 2022 · 3 min read · bash linux openstack pci nvidia  ·
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    1Failed to build and run instance: libvirt.libvirtError: internal error: qemu unexpectedly closed the monitor: 2022-08-05T12:05:46.630755Z qemu-system-x86_64: -device vfio-pci,host=0000:c3:00.0,id=hostdev0,bus=pci.0,addr=0x5: vfio 0000:c3:00.0: group 15 is not viable 2Traceback (most recent call last): 3 File …


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  • tcpdump HTTP traffic

    calendar Aug 3, 2022 · 1 min read · bash linux  ·
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    If you want to diagnose HTTP traffic it's sometime usefull to use tcpfump to dump the packets either on the console or to a tile Here is a nice litte command I found to run a dump of all http traffic on a defined port tcpdump -A -s 0 'src 10.10.110.254 and tcp port 5000 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - …


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  • List all local linux disks

    calendar Aug 1, 2022 · 1 min read · bash linux  ·
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    I was writing a script to interact with all local disks and i needed a simplied list of local disks, not partitions and not the loopback mounts..This is what I came up with lsblk -d | cut -f 1 -d" " | tail -n +2 | grep -v loop Which will give you a nice parseable output something like this 1sda 2sdb 3nvme0n1 …


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  • MaaS CLI

    calendar Jul 13, 2022 · 1 min read · maas linux  ·
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    The MaaS CLI documentation is a bit trash Login to MaaS maas login admin http://10.10.110.250:5240/MAAS/api/2.0/ 5HvxATpW5487XmkSjZ:CXfC3McdvV9U9aefbp:wB9jGT8AJ4DUYArJ8dDqeRVczBwJEXMk Set the IPMI Cipher Suite ID to 'freeipmi-tools default' maas admin machine update bfyq3e power_parameters_cipher_suite_id='' Commission …


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  • Add suer to docker group

    calendar Apr 6, 2022 · 1 min read · linux bash  ·
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    It feel like every time I run docker ps I get blah blah blah, permission denied The simple oneliner fix.. And the bonus, you dont even need to log out :) sudo usermod -G docker -a $USER && newgrp docker


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  • Network monitoring tools

    calendar Oct 21, 2020 · 1 min read · linux networking  ·
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    bmon Nethogs Glances Warning dependency heavy


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Cory Hawkvelt photo

Cory Hawkvelt

CTO @ Nexgen Cloud | Career Nerd and Open Source Cloud Architect
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Recent Posts

  • Converting Cisco AirAP3802i to Mobility Express Mode
  • Mastering SSH Certificates: A Comprehensive Guide
  • My First Dabbling with LoRa
  • Deploying pam_ussh: A Comprehensive Guide
  • Validating SSH Certificates with a Local CA Using Python
  • Unpacking the NVIDIA H100 Tensor Core GPU: A Deep Dive for CTOs
  • Caddy proxy for OpenStack API's
  • HP Server ACPI errors

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