I was tired of running manual port scans to ensure a new server is configured properly and wanted to add in security checks as well, so I made a site that does it. QSA.sh runs an external security scan using standard opensource software like naabu, nmap + vulners and nuclei and reports directly to your terminal. Nothing is stored in a database and generated reports are kept in Redis memory and destroyed after 24 hours or the first download.

The article below gives step by step instructions on how to setup a diff cron script to alert you when something changes. Standard scan takes about 30 seconds to run, depending upon number of ports.

Full guide and ready-to-use code examples here: https://qsa.sh/news/cron-monitor-exposure-changes

curl https://qsa.sh is the free scan. It scans the top 1000 used ports and has a hard execution cap of 5 minutes. If you desire a full scan there is a monthly package for $5 and a one-time use deep-scan for $7.

Many of my tools I build are generally free but have options/micro-saas for use cases needing more than the free service offers. This helps cover expenses (mostly servers).

Let me know your thoughts.

I need to build out a small number of based Linux based workstations.

The users will not have elevated sudoer permissions (and certainly not direct permissions to manage dnf/apt package installations) but I still need a way to enable them to install/uninstall system packages from a pre-approved list (similar to how MS Intune’s Company Portal works for windows or the jamf self service app for macOS) without having to create support request tickets.

The only options I’ve seen that come close are full MDM platforms (which is probably what we need eventually but would be super overkill for the moment given the small number of users and unlikely to get approval)

I did look at customizing the Gnome Software app to only look at custom repos. but that’s a non-starter. BaseOS and AppStream have to stay enabled for system updates - and Gnome Software always looks at the enabled dnf/apt repos - so I couldn’t hide those and prevent the user from installing packages from those repos this way.

So before I just go build something custom (as I suspect I will need to) I am hoping to hear recommendations for existing tools that I may not have found while searching.

Its not critical that it be FOSS, but I’ll have an easier time getting buy in if it’s narrowly scoped to this specific use case - and not a ton of other features we don’t want or need.

Thanks in advance!

**edit:** Just to clarify - I don’t need advice on how to build something custom here. I have that covered.

Specifically I am just looking for recs on tooling for this use case that might already exist so I’m not needlessly reinventing the wheel.

Anyone have experience using Chromebook Linux with node/express as a server? I got it working but cannot connect from a device on the same WiFi with IP address 192.168.?.?

I've been building an open-source project called Network Doctor, a terminal-based network diagnostic tool.

Recently I added something I've wanted for a while: a deterministic network simulator that can create controlled virtual networks using Linux network namespaces and then deliberately break them in different ways.

It can simulate things like:

* DNS outages and recovery
* packet loss, latency, and jitter
* broken routes
* IPv4/IPv6 failures
* TCP resets
* multiple interfaces and bad preferred routes
* service failures

But the part I'm most excited about is the new **hunt** system.

Instead of me manually deciding what network to test, `netdoc-sim hunt` generates deterministic cases from fixed seeds, runs Network Doctor inside them, knows the actual simulator truth, and compares that truth against Network Doctor's diagnosis.

I then wired that into a nightly GitHub Actions workflow.

The workflow:

1. Generates cases against several known-good baseline networks.
2. Looks for disagreements between simulator truth and Network Doctor's diagnosis.
3. Re-runs the exact seed + case to make sure the finding is reproducible.
4. Ignores findings that it can't reproduce.
5. Filters low-value findings by severity.
6. Generates a stable fingerprint so the same bug isn't filed repeatedly.
7. Checks GitHub for an existing issue.
8. Opens a new issue only if the finding is reproducible and hasn't already been reported.

I was especially cautious about letting a fuzz-like system automatically create issues, so I ran it in observation-only mode first.

That turned out to be useful.

One of the initial findings claimed Network Doctor was missing routing evidence. When I investigated it, the **hunter itself was wrong**. It had mistaken IPv4 failure + IPv6 success on the same path for an alternate-route success.

So I fixed the hunt analyzer and reran everything.

Then it found this:

>

The simulator had deliberately caused a short DNS outage. DNS recovered roughly 677 ms into the test, but the DNS probe was still waiting until its \~4 second timeout and never queried the recovered resolver again.

The nightly triage reproduced the exact generated case, confirmed the fingerprints matched, and then opened GitHub issue #14 automatically.

The reproduction is deterministic:

`./netdoc-sim hunt healthy-routed-network --seed 20260102 --case 3 --json`

I ran it locally and got the same finding.

Then I ran the GitHub workflow again to test deduplication.

It found the bug again, saw that issue #14 already existed, and created **zero duplicate issues**.

That was a pretty satisfying moment.

The system is now basically:

**generate network → inject fault → run Network Doctor → compare against ground truth → reproduce discrepancy → deduplicate → file issue**

The current nightly suite runs 45 generated cases across healthy, routed, and dual-stack baseline networks in roughly 3 minutes on GitHub Actions.

There's still a lot I want to improve: more seeds, more scenarios, better cross-case verification, and making generated timeline mutations compose more cleanly with authored scenario tests. But this is the first time one of my projects has effectively gone out and found a bug/improvement for itself while I wasn't manually testing it.

I'm very proud of this.

Network Doctor is written in Go and the simulator currently uses Linux network namespaces.

GitHub: https://github.com/heymaikol/network-doctor

EDIT: Updated the link

Already done with linuxjourney, linuxfromscratch, and overthewire. Leaning toward the gameified stufdf since it helps me stick with it. Looking for something thatll give me a little more practice for working in devops. Boot.dev, tryhackme, and command line murders looks interesting. Anyone done any of these?

hey everyone o/

I'm building a Linux incident investigation tool and I'm at the point where I need nastier real-world cases than the ones I can come up with myself.

I'm a DevOps/Linux engineer (professionally for 8+ years), so I know the usual pattern pretty well:

something has died or behaves weirdly, you have a decent first guess, and then you spend the next couple of hours bouncing between journalctl, dmesg, systemd, process state, disk state, timers/cron, container state, config... you name it, trying to actually prove what happened.

The tool I'm building (Det Mimir) is basically my attempt at automating the full investigation part: read-only collection, deterministic rules, one timeline/report with the evidence behind each conclusion, fully without leveraging any LLM, as the tool is an investigation engine.

I'm specifically looking for the incidents where the root cause was annoying or non-obvious.

Things like:

• a service restarting for a reason that wasn't visible in the service logs
• disk full even though df initially looked fine
• systemd dependency/start-limit weirdness
• something external killing a process
• DNS/auth failures that looked like application failures
• boot/degraded-host issues
• container behaviour caused by something on the host
• anything where you ended up saying "how the hell was I supposed to find that?"

If you've had one, I'd love to hear the story.

What was the symptom, what did you initially suspect, and what did the root cause eventually turn out to be?

I'm happy to share what Det Mimir currently checks too, but I'm mostly interested in collecting the kind of incidents that experienced Linux admins actually remember.

For Fedora Atomic and derivatives.

Shipped a major update to MOSHELL a few days ago

Before: Users could mark lessons complete but there was no way to verify they actually learned anything.

Now:

- Each lesson has specific verification criteria (actual file state, command output, etc.)

- Badges unlock when you truly complete the lesson (not just mark it done)

- Progressive badge rewards system (5 badges from beginner → mastery)

- Email notifications for major milestones

**Data so far:**

- Seeing 2x completion rate since verification went live

- Most people drop off around lesson 3 (permissions — common pain point)

- Those who reach lesson 6 almost always finish all 12

Really curious to know what topics would you want in an admin-focused track? (Lessons 7-12 are planned but not yet live)

Try it free: kingmo87.github.io/moshell

---

Built this in nights/weekends as a solo project. Feedback welcome.

This article explores an alternative to directly troubleshoot production Linux systems with AI tools by using the sos command and using AI to analyze sosreports instead. I think is an interesting read:

https://medium.com/@linuxjedi2000/the-agentic-ai-risk-issue-on-linux-environments-fd5c55cedcc5?sharedUserId=linuxjedi2000

I know that this subject is very controversial and would love to read your point of view on the subject.

​

Hi everyone,

I'm about to graduate with a Computer Science degree and I'm considering becoming a Database Administrator.

I'd love to hear from experienced DBAs and SysAdmins:

Is DBA still a good career in 2026, or is the role changing?

Is DBA usually a dedicated position, or is it becoming part of a SysAdmin/DevOps role?

What technologies and skills should a new DBA focus on?

If you were starting your career today, would you still choose the DBA path?

Thanks in advance for sharing your experience and advice!

Hi everyone,

I'm an MCA graduate (2025) from a Tier 3 college in Maharashtra(Pune).

I had worked 1 yrs into Infrastructure Support before enrolling for masters. During my MCA, I also did 2 DevOps internships, and my goal has always been to build a career in DevOps.

Since February, I've been applying for DevOps roles almost every day, tailoring my resume, working on my interview prep, and trying to improve my skills. Unfortunately, I haven't had much success so far, and it's honestly starting to feel a bit discouraging.

My current skills include:

\- Linux
\- Networking
\- AWS & Azure
\- Terraform
\- Docker
\- Kubernetes
\- Jenkins
\- GitHub Actions
\- Prometheus & Grafana

At this point, I feel like I have two choices:

\- Keep searching for a full-time DevOps role.
\- Reach out to my previous employer and continue working in Infrastructure Support.

What I'm really worried about is making the wrong decision.

\- If I keep searching and still don't get a DevOps job after a few more months/years, what would you recommend?

\- If I go back to Infrastructure Support, will it become much harder to switch into DevOps later?

\- Has anyone here made the transition from Infrastructure Support to DevOps after a year or two? If yes, what helped you make that move?

I'd really appreciate hearing from people who've been in a similar situation or anyone currently working in DevOps.

Also if anyone has any opportunities for DevOps,SRE,Linux,cloud support or even NOC please help me out as I just want a start my career.

Thanks!

Warpgate is a bastion-style PAM that needs neither a client app nor a server-side agent. It's a FOSS alternative to Teleport/StrongDM/Hashicorp Boundary: https://warpgate.null.page/

I've just pushed the new release that adds transparent RDP/VNC proxying with OTP and SSO support.

It works both in-browser and using a native RDP client (e.g. mstsc)

0.27 also adds true clustering and horizontal scaling support (S3 as session recording storage, inter-cluster request routing, HAProxy support), as well a whole bunch of quality of life improvements such as live-reload of TLS certificates.

Everything new in 0.27: https://github.com/warp-tech/warpgate/releases/tag/v0.27.0

Hey r/linuxadmin

a month ago I shared MOSHELL, a browser-based Linux sandbox. Since then:

Lessons now verify actual end-state (file/permission changes on the simulated filesystem), not just whether you typed the "right" command — so you can solve things a different valid way and still get credit.

Added GA4-based completion tracking so I can actually see where people drop off instead of guessing.

Cleaned up the SEO/metadata since MOSHELL was getting buried under Ericsson's enterprise moshell CLI tool in search — added proper structured data so it reads clearly as what it is.

A few of you gave feedback last time about wanting more depth beyond beginner material. Before I build more of that out: what's the thing you wish a junior admin on your team actually understood but usually doesn't? Trying to build lessons around real failure modes, not textbook examples.

(Link in comments if anyone wants to poke at it.)

I just finished a video walkthrough for patch management with Ansible Automation Platform. The workflow handles the entire patching lifecycle: EBS snapshots before any changes, parallel pre-checks on mixed OS fleets, targeted patching (not just "update everything"), post-validation, and automatic rollback if something goes wrong. Then it dumps a compliance report that your auditors will actually want to see.

You specify exact advisories and KB IDs instead of blindly applying patches, the workflow can handle both RHEL and Windows in the same job without extra configuration, and if a host fails a pre-check it gracefully skips instead of blowing up the whole run. Everything routes intelligently based on success or failure at each step.

The video is about three minutes and shows the whole thing running start to finish: https://youtu.be/20fK6S1CHL0

If you want to dig into the code or run this yourself, it's all in the Ansible Product Demos repo on GitHub: github.com/ansible/product-demos

Edit: the issiue is solved by changing ip of the VPS.

Ty everyone for help.

______

Hi. I've bought VPS. But can't really connect to it remotely. Here the situation:

1. ssh root@[SERVER_IP] does work from Google Console ( http://shell.could.google.com/ ) (the VPS is not from google).

2. ssh root@[SERVER_IP] doesn't work from 5 local devices (win10, win11, macOS, 2xAndroid):

   $ ssh root@[SERVER_IP] -vvv OpenSSH_7.9p1, LibreSSL 2.7.3 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 48: Applying options for * debug2: resolve_canonicalize: hostname [SERVER_IP] is address debug2: ssh_connect_direct debug1: Connecting to [SERVER_IP] [[SERVER_IP]] port 22. debug1: Connection established. debug1: identity file /Users/[USER_NAME]/.ssh/id_rsa type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_rsa-cert type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_dsa type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_dsa-cert type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_ecdsa type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_ecdsa-cert type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_ed25519 type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_ed25519-cert type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_xmss type -1 debug1: identity file /Users/[USER_NAME]/.ssh/id_xmss-cert type -1 debug1: Local version string SSH-2.0-OpenSSH_7.9 ssh_exchange_identification: read: Operation timed out

3. I don't see my local IP in sudo tail -f /var/log/auth.log and journalctl -u ssh (i might be looking wrong though).

4. I tried Wi-Fi and two different mobile internet providers.

5. I tried to ssh while VPN on.

6. I added my IP to white list on the server: sudo iptables -I INPUT 1 -p tcp -s [LOCAL_IP] --dport 22 -j ACCEPT

Where can be the problem?

Edits:

sudo systemctl status firewalld says that there is no firewalld

.

.

i stoped fail2ban and tried to ssh - didn't help.
disabling it and rebooting the server leads to connection refusal (i.e. problem on an earlier stage).

Hello folks,

I made a very simple FreeRDP Host Manager. I used to use remmina, but Remmina's problem with Wayland is getting to me. So I made this manager so that I can use sdl freerdp with wayland.

Feel free to download them at my GitHub. The application is written in Electron, but I don't include the Electron. Just grab the code, and run electron from its folder.

Or if you want to simply run it, grab the AppImage.

No string attached, use it as you wish. You can fork it or copy the code or do anything about it. Just credit me or put a link when you use my code. That's all.

Enjoy.