Find Linux System Administration Projects

need to configure SMTP in osticket (old) PHP
self-hosted ticketing system.
+ check SMTP configuration on another VPS host

osticket another server and SMTP another server (ArmaLinux 8 + OLS + dns)

I am looking to fix an issue on my linux server. I have been running a script for about 2 years without issue and all of a sudden a week ago I have been getting a segfault isssue and it fails to run. I have not updated anything, I have tried to apply numerous fixes but have not found any. Looking for someone else to try and figure this out for me with more experience.

This is the error:

[104794.937188] php-cgi[10352]: segfault at 2b0ed6e0f9d8 ip 00002b0ee192fc97 sp 00007ffc8c14c998 error 7 in libxml2.so.2.9.1[2b0ee182b000+15e000]

We're looking for someone to help us move our web apps from Digital Ocean servers to our local workstation. If you’ve got experience managing Linux servers and deploying applications with Nginx, Node.js, Postgres, and Docker, we'd love to chat with you!

We are seeking an experienced DevOps engineer to manage and optimize our server infrastructure. The ideal candidate will have expertise in configuring Nginx, managing PM2 processes, and implementing SSL certificates. Additionally, knowledge of port and DNS configurations is crucial. You will work closely with the development team to ensure our application runs efficiently and securely. If you have a proactive approach and a passion for optimizing server performance, we would love to hear from you.

We are looking for an experienced developer to assist with the deployment of a Node.js application on a VPS using Nginx and PM2. The ideal candidate will diagnose and fix deployment issues to ensure that our application runs smoothly and efficiently. You should have a solid understanding of server management and application deployment best practices. If you are passionate about optimizing application performance and have a proven track record, we would love to hear from you!

Need specific help in connectivity to RHEL with Putty CAC using CERTS

I am looking for the support of a professional with strong expertise in AWS and AWS cost optimization to identify potential areas of waste in my AWS account.

I have been using AWS for 12 years; the infrastructure works well and the application running on it is stable. This is a mission-critical application, so I have always followed the philosophy of having five backups more rather than five fewer, for safety reasons. Since the business is doing well, I do not need to aggressively optimize or “cut corners”: I can afford to have one extra layer of protection rather than one less.

However, having said that, I believe I have some cost inefficiencies, because if in one month I spend X and then proceed to purchase Reserved Instances, the following month—instead of spending X minus a percentage—I end up spending X plus a percentage. This is a clear sign that I am doing something fundamentally wrong at a conceptual level.

We are seeking a skilled freelancer to assist with the installation of n8n on a Linux server. The ideal candidate will provide a comprehensive step-by-step guide that details the installation process, ensuring that it can be easily replicated. Your expertise in Linux environments and familiarity with n8n will be crucial for this project. If you are proficient in creating clear and concise instructions, we would love to hear from you!

Instalation of n8n platform on linux (ubuntu server) 
Doker instalation
Suports multiple instances with redis in doker 
Postgres will be on different serwer ( will provide connection string)
Support of custom domain
Vitrual server (vps) on ovh
Will need dull instruction how to reinstall all(includes all commands)  
Self generated certyficate (lets encrypt)
Reverse proxy (on nginx?)
N8n in worker instance
Large file storage (azure connection string provided)

***Reasonable per hour rate or price estimation required ***

We are looking for an experienced network engineer to configure multiple external domains pointing to a single IP address, routed to various VMs and LXC containers using Traefik on Proxmox VE (PVE). The ideal candidate will have a solid understanding of networking principles and experience with Traefik, virtualization, and container management. You will be responsible for ensuring that all domains are correctly routed and that traffic reaches the appropriate containers and VMs seamlessly.

I need an experienced server administrator to optimize my LiteSpeed server and WordPress site for maximum performance.

🖥️ SERVER SETUP:
- VPS: 12 vCPU, 48GB RAM, 300GB SSD
- OS: AlmaLinux 9.7
- Control Panel: Webuzo
- Web Server: LiteSpeed (active)
- Platform: WordPress (high-traffic)

🎯 GOAL:
- GREEN scores on PageSpeed Insights (90+ mobile & desktop)
- GREEN scores on GTmetrix (A grade)
- Fast loading with ALL plugins working
- Site uses Makfast image plugin (MUST stay active)

✅ REQUIRED TASKS:
1. Configure LiteSpeed Cache properly for WordPress
2. Setup Redis or Memcached for object caching
3. Optimize PHP-FPM settings for available RAM
4. MySQL/MariaDB performance tuning
5. Identify and resolve plugin conflicts (document them, don't just disable)
6. Database optimization and cleanup
7. Server-level caching configuration

🔒 IMPORTANT:
- If you find plugin conflicts, document:
* Which plugins conflict
* Error logs
* Your recommended solution
- NO removing features to fake good scores
- Makfast plugin must remain active and functional
- Backup before any changes
- Provide simple documentation of all changes made

📋 DELIVERABLES:
- Optimized server with green PageSpeed/GTmetrix scores
- List of changes made (commands, configs modified)
- Report of any plugin conflicts found
- Brief guide on maintaining the optimization

⏱️ TIMELINE: 1-2 days

💰 BUDGET: $100 fixed price

Please start your proposal with "LITESPEED-OPT" and include:
- Your experience with LiteSpeed + Webuzo
- Brief explanation of your approach
- Examples of similar projects

NO generic proposals. Show me you understand the requirements.

We have a containerized application that scales correctly with Docker Compose. When we scale the same application with Docker Swarm or Kubernetes, the 3rd or 4th instance stops working (becomes unresponsive / fails health checks / stops serving traffic). The application produces extensive logs.

We are looking for an experienced container/orchestration debugging specialist who can investigate this systematically, identify the root cause, and propose or implement a fix.

What we need
- Reproduce the failure on Kubernetes (you will get 2 bare metal servers to set it up, if needed)
- Collect and analyze evidence (app logs, container logs...)
- Identify the root cause
- Provide a clear remediation plan and implement changes if agreed
- Deliver a short write-up documenting the cause, fix, and prevention steps

Tech context
Container runtime: preferable containerd
Orchestrator:preferably Kubernetes (self-hosted)
Deployment: manifests
Observability: logs available

Deliverables
- Root cause analysis
- Patch / configuration changes (only if they can be done from a devops perspective, no custom plugin development or app modifications)
- Validation that scaling beyond 10 replicas is stable

Project Overview

We are building a self-hosted email hosting system to be fully integrated into our CRM SaaS platform.

This is not an email marketing system.
The goal is to provide standard email hosting (send / receive / reply) for platform users, fully managed internally and exposed through a robust API.

We are looking for a senior-level architect and hands-on engineer who can design the architecture, validate the technical approach, and assist with the implementation of a scalable, multi-tenant email infrastructure, hosted entirely on our own servers.

Key Requirements

100% self-hosted email infrastructure
No dependency on third-party email providers (SES, SendGrid, Mailgun, etc.)
Full control over SMTP, IMAP, POP3, DNS, and email reputation
Multi-tenant SaaS architecture
Isolated companies (tenants)

Each company can manage:

One or multiple custom domains
Multiple users and mailboxes
Shared mailboxes (e.g. support@, sales@)
Clear ownership: company → domain → mailbox → user(s)

Scalable by design

Architecture must scale horizontally
Increasing volume or number of mailboxes should require only additional resources, not architectural changes
No hard limits on email volume by design
API-first system

Expose APIs for:
Domain management (add / verify / remove domains)
User creation & management
Mailbox creation (per user and shared)
Permissions & access control
Email status and events
APIs will be consumed by our CRM SaaS platform
Event & webhook system

Internal events for:
email_sent
delivered
opened (if applicable)
replied
bounced (soft / hard)
spam complaints
Events must be usable for CRM workflows and automation

Technical Scope

You will be responsible for architecture-level decisions, including but not limited to:

Email protocols: SMTP, IMAP, POP3
DNS & deliverability:
MX records
SPF, DKIM, DMARC
Domain verification flows
Inbound & outbound mail flow
Bounce handling & feedback loops
Rate limiting, throttling, and abuse prevention
IP reputation management and warm-up strategies
Logging, monitoring, and auditing
Data retention & GDPR-friendly design

Expected Responsibilities

Phase 1 – Architecture & Design

Propose a complete high-level architecture
Define core components and responsibilities
Design email flows (send / receive / reply)
Define API contracts and data models
Identify risks and mitigation strategies

Phase 2 – Technical Design

Detailed system design
Deployment & scaling strategy
Security and isolation model
Event & webhook architecture

Phase 3 – Implementation Support

Hands-on development or close collaboration with our internal team
Code reviews and architectural guidance
Support during integration with the CRM platform
Required Experience
Proven experience designing or building:
Email service providers
Messaging platforms
Or large-scale email infrastructure
Deep understanding of:
SMTP, IMAP, POP3
Email deliverability & reputation
DNS (MX, SPF, DKIM, DMARC)

Strong background in:

Multi-tenant SaaS architecture
API design
Event-driven systems
Experience with self-hosted infrastructure (bare metal or cloud)

Nice to Have

Experience with Postfix, Dovecot, Amavis, Rspamd, or similar
Experience with queue-based or event-driven systems (Kafka, RabbitMQ, Redis, etc.)
Familiarity with CRM or communication platforms
PHP backend experience (optional, not mandatory)

Engagement Model

Initial architecture & design phase (fixed-price)
Followed by long-term collaboration for implementation and scaling
We value clean design, long-term thinking, and ownership, not quick hacks

Description:
We are seeking an experienced AWS/DevOps professional to assist us in regaining access to our EC2 server. The ideal candidate will have a strong background in AWS services and server security. You will be responsible for generating a new PEM key, restoring secure access, and ensuring our platform (website, admin panel, and app backend) is properly connected and operational.

Responsibilities:
• Generate a new PEM key for EC2 server access
• Configure server access for existing team members
• Ensure website, admin panel, and app backend are properly connected
• Apply basic security best practices for server access

Skills Required:
• AWS EC2 Management
• Server Access Recovery
• Cloud Infrastructure Setup
• Security Best Practices
• Troubleshooting

Notes:
• We do not have the original PEM key, so this will require creating a new one and reconnecting the server with our platform.
• This task is focused solely on restoring access and proper server setup.

We are seeking a skilled Linux System Administrator to manage and maintain our Linux servers. The ideal candidate will have a strong understanding of system performance tuning, security, and backups. You will be responsible for troubleshooting system issues and ensuring high availability. If you have a passion for Linux and a knack for solving complex challenges, we want to hear from you!

I created a server on Hetzner using an SSH key. For some reason, I disabled the SSH key and enabled password-only login. Now I am unable to log in either with the password or with the key.

I need someone who can remotely access my system and fix the issue using Hetzner’s console mode.

🛡️ Advanced Click-Fraud Detection & Defense System – Senior Backend Developer Needed (Linux / Nginx / Fingerprinting / Bot Detection)
Project Overview

We are building one of the most advanced Google Ads click-fraud detection and defense systems in Europe.
The system must reliably detect:

rotating mobile proxies

device emulators

headless browsers

automated mouse movement

synthetic scroll behavior

fingerprint manipulation

high-volume botnet attacks

cross-domain attack patterns

We already have a working prototype with logging, dashboards, and Nginx blocking logic.
Now we want to rebuild the entire system professionally, with enterprise-level architecture and intelligence.

We are looking for a high-level backend engineer who can build a scalable, modular, and secure system based on the specification below.

🔧 Required Skills

Mandatory:

Linux server administration (Debian)

Strong backend development (PHP or Node.js)

Advanced experience with Nginx, rate-limiting, maps, and dynamic blocklists

Database architecture (PostgreSQL preferred)

Event logging systems (structured logs, ingestion pipelines)

Experience with fingerprinting, bot detection or anti-fraud systems

Security mindset (heuristics, anomaly detection, behavioral patterns)

Bonus:

WebSockets / realtime dashboards

MaxMind GeoIP2 / ASN experience

Experience with ad fraud prevention tools

Experience building risk scoring systems

📌 What We Need Built (Technical Scope)

This is the full system we want developed.

1. Client-Side Tracking (JavaScript)

Build an advanced JS tracker injected on multiple websites.

Required Fingerprint Data:

userAgent

platform

language, languages

screen size & devicePixelRatio

timezone

hardwareConcurrency

maxTouchPoints

navigator.webdriver (automation flag)

touch vs mouse support

stable client_id via localStorage

generate fingerprint_hash (SHA256)

Required Behavior Tracking:

time to first scroll

time to CTA click

scroll depth

total scroll events

total click events

click elements (selectors)

session duration

optional: mousemove sampling (variance, jitter, intervals)

Bot Challenges (Honeypots):

invisible clickable element (should never be clicked)

CTA activation delay (bots click too early)

hidden honeypot input field

All challenge triggers must be logged.

2. Backend Ingestion API

Build a secure API to receive all client events:

POST /api/event

Inputs include:

client_id

session_id

event type

fingerprint data

behavior data

IP address

user agent

timestamp

domain / campaign metadata

API must include:

basic auth or secret key

rate limiting

input validation

logging failures

3. Database Architecture (PostgreSQL Preferred)
Tables Required:

clients (global user identifiers)

fingerprints (hash + raw JSON)

sessions (domain, campaign, timeline, score, status)

events (pageviews, clicks, behavior, challenge results)

subnets (/24, /20 patterns, statistics, risk scores)

alerts (attack detection, anomalies)

blocklist (ip / cidr / client / asn with TTL)

Must support:

high-volume inserts

fast querying

cleanup / TTL expiration

4. Risk Engine (Core Intelligence)

Build a configurable 0–100 risk scoring engine based on:

Geo / Campaign Mismatch

unexpected countries

unusual geo spikes

IP / Subnet / ASN Heuristics

repeated clicks from same /24

rotating IPs for same client

proxy / hosting ASNs

shared patterns across domains

Fingerprint Consistency

impossible combinations
(e.g., iPhone UA + no touch + desktop resolution)

navigator.webdriver = true

fingerprints repeating with different IPs

Behavioral Anomalies

CTA click 2 seconds after load

zero scroll events

identical behaviour across multiple sessions

mouse movement uniformity

Bot Challenge Results

invisible element clicked

CTA clicked before activation

honeypot form filled

Cross-Domain Correlation

If the same fingerprint or client triggers clicks across multiple independent websites (e.g., 3 clients’ sites), this is extremely suspicious.

Risk Levels:

0–30 = clean

30–60 = suspicious

60–100 = fraud detected

Risk score should trigger:

alerts

temporary blocks

logs

configurable thresholds

5. Automatic Blocking System

Backend must generate dynamic blocklists:

IP

CIDR (/24 or /20)

client_id

optionally ASN

Nginx Integration Must Include:

generated map files

TTL expiration (auto unblocking)

automated reload (graceful)

whitelist support for:

Google

internal staff

partners

6. Dashboard (Admin Interface)

A secure dashboard showing:

Global Overview

total clicks (24h)

suspicious traffic

blocked IPs

country heatmap

attack timeline

Session Inspector

Per-session deep dive:

events in chronological order

fingerprint data

behavior data

cluster patterns

honeypot results

cross-domain correlations

Subnet Intelligence

top subnets by risk

ASN breakdown

repeated offenders

Alerts Panel

attacks detected

anomalies

high-risk spikes

Controls

block/unblock IP or CIDR

change risk score

mark session as legit (training data)

WebSockets for realtime updates is a plus.

🎯 Final Deliverables

Full backend system (API, DB, risk engine, blocklist generator)

JS tracker with advanced fingerprinting & behavior logging

Nginx auto-blocking integration

Dashboard for analysis & actions

Documentation for deployment

Code must be clean, modular, scalable

💬 To apply, please answer these questions:

Have you built anti-fraud / bot-detection systems before?

Do you have experience with fingerprinting libraries or custom fingerprinting?

Which backend language do you prefer (PHP or Node.js) and why?

Can you design a risk-scoring engine based on heuristics?

Can you integrate dynamic blocklists into Nginx?

What would be your estimated development time for this project?

Please include relevant portfolio examples or GitHub repos.

I need assistance with a startup issue on my computer. Whenever I boot up my system, both the Device Manager and Windows Command Prompt open automatically, which is disrupting my workflow. I'm looking for a skilled professional who can diagnose the cause and implement a solution to prevent these applications from launching at startup. If you have experience with Windows troubleshooting and system configuration, please reach out. Your expertise will help me restore normal startup functionality.

We are seeking an experienced freelancer to assist with upgrading our n8n Docker installation. The primary task involves updating the PostgreSQL database from version 11 to version 16 while ensuring minimal downtime and data integrity. The ideal candidate will have a strong understanding of Docker, n8n workflows, and PostgreSQL upgrades. Familiarity with troubleshooting potential issues during the upgrade process is crucial. If you have the required expertise and can deliver results efficiently, we would love to hear from you!