Category: linux

xmrig with cuda for Rocky Linux 8.5

Matthew Heick Leave a comment

The wife wants to get into Cryptocurrency, so we get into Crypto.

She picked out a couple: VeChain(c), Stellar(c), and Bitcoin(c)

I picked out a couple: Ethereum(c), Monero(c), and Dogecoin(c)

None of them intersect, so I’ll start with my list first 🙂

First thing is to build a miner, and we’ll use an old Intel Core2 Quad Q9650 with 8GB RAM and an nVidia GeForce GT710 that I scrounged together from old parts.

Second thing is to choose a cryptocurrency to see how we can optimize it. Monero looks ezpz.

Third thing is to get familiar with xmrig and xmrig-cuda built and running. We’ll plan and build this in a Virtual Machine to make sure we have all our dependencies ironed out before committing this to an actual machine. We’ll steal some guidance from Litaiem Moatez and their first linkedin article to help us out.

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ssh port forwarding / ssh tunneling

Matthew Heick Leave a comment

I’ve always been curious on ssh port forwarding enough to experiment and learn it to be deadly enough. I currently have two machines that I’d like to test this with, both -L (local) and -R (remote).

I have a C7 host behind a router and a C8 host on the internet that I’ll be testing with.

Our set up is the following:

192.168.2.222:22 (c7 Host) <-> 192.168.2.1:* (router) <-> 159.203.99.198:22 (c8 host)

Local Forwarding

What I’m going to do is forward port 4444 on my c7 machine to connect to the c8 host on port 22 by launching the following on 192.168.2.222:

$ ssh -L 192.168.2.222:4444:159.203.99.198:22 localhost

At this point I can start a SSH session to 192.168.2.222 at port 4444. I’m prompted to log in at 159.203.99.198, and i’m good to go. As long as the command is running I maintain a connection.

To remove the login necessity I added ~/.ssh/id_rsa.pub to ~/.ssh/authorized_keys for passwordless local log in.

Remote Forwarding

Remote forwarding allows world-accessible hosts to provide access to internal hosts. In our previous scenario we forwarded from an intranetwork host to a world host. Now we’re gonna use that intranetwork host and make it so that if we SSH to the world host at port 4444 that we will be ssh-ing to our intranetwork host, bypassing the router.

On 192.168.2.222 I execute the following:

$ ssh -R 4444:localhost:22 159.203.99.198 -ldiffuser

On my world-accessible host I log in with “diffuser”, and the forwarding is set up.

On 159.203.99.198 I can ssh to localhost:4444 and connect as internaluser with ease:

$ ssh localhost -p 4444 -linternaluser

Due to how /etc/ssh/sshd_config has GatewayPorts set up by default I cannot connect with my home computer to my world-accessible host. I would have to restart sshd service after setting GatewayPorts=yes (by default it’s no)

Smaller mkv with ffmpeg

Matthew Heick Leave a comment

When you run a Plex Media Server you know that family and friends ask for specific content to be placed on it so they can watch it. It comes down that a “popular” series just finished up all 9 of their episodes and the wanted it to exist on our Plex. I was able to find the asked content, but was a bit surprised when the video content was a spectacular 1080p but the audio content defaulted to Brazilian Portuguese.

Lucky for me there was an English audio stream as well, but I felt it annoying that if I wanted to start watching this and have to swap to the secondary audio track every time. With the power of ffmpeg[static] and a couple smart command-line parameters I was able to re-make my videos with English as the default language and cut out all the unnecessary data.

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Learning Docker: Take 1

Matthew Heick Leave a comment

It was time. I’ve been waiting for enough time to learn Docker and begin to get familiar with it. I’ve heard of it, seen it in action, and thought it was the coolest thing in the world and I had to learn it. I decided to take the dive off the actual Docker ship and descend into the depths.

So, I found a YouTube video from the Docker YouTube video channel (link: https://youtu.be/iqqDU2crIEQ). Albeit it provided me some terminology and knowledge, it didn’t really tell me everything I wanted to know, like some under-the-core or how docker did the docker thing. I learned how to build, ps, port forward, docker hub, and a Dockerfile, but then they went to docker-compose and I got lost.

So, after sitting on that video and registering all the information I decided to set a goal: Load minecraft in a docker container. This shouldn’t be difficult, as it requires java, some source files, and that should be simple.

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SimpleSAMLphp / quick&ez

Matthew Heick Leave a comment

Background: For about 5 years at my place of work we have used a software called SimpleSAMLphp to help offer identity solutions to TVE (TV Everywhere) customers. In essence I have been one of a team of 20th century cable people.

This software, in it’s current version has been heavily customized to offer quick deployment solutions for new customers. All I can say is that it’s awesome running an Identity Stack with 50+ IdPs and 5000+ SPs.

I decided to see how quick I could set up a SAML SP -> IdP relationship between two Centos 7 Virtual Computers:

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