Dec 2026 — PRESENT
Senior Technical Support Engineer · Linux hosting, web stack troubleshooting, security investigations and root cause analysis.
I Build,
Troubleshoot & Secure Linux Infrastructure.
I'm Daniel Dass M, a Senior Technical Support Engineer working with Linux hosting, web server troubleshooting, infrastructure security and server operations. I'm expanding my skills through hands-on AWS projects.
Evidence first. Fix the root cause.
My work involves diagnosing Linux hosting and web application issues, analysing logs, investigating resource spikes, troubleshooting DNS, SSL, databases and email services, and supporting safe service recovery. I value clear communication, practical troubleshooting and continuous learning.
Every incident ends with a written root cause: what broke, why it broke, how it was fixed and what stops it happening again.
NAME="Daniel Dass M" ROLE="Senior Technical Support Engineer" EMPLOYER="Hosting.com" UPTIME="since Nov 2021" FOCUS="Linux, web servers, security" CERTIFICATIONS="AWS, RHCSA, Azure" SHELL=/bin/bash
Professional journey
Explore my professional background in Linux hosting, technical support, web-server troubleshooting, incident response and infrastructure operations.
Nov 2021 → Nov 2023
Technical Support Engineer · Hosting support, website issues, server configuration and troubleshooting.
Skills & technologies
running: used in day-to-day work learning: hands-on practice and study
linux-systems.target
- linuxrunning
- sshrunning
- bashrunning
- systemdrunning
- log-analysisrunning
- amazon-linuxlearning
- rhel (RHCSA prep)learning
web-hosting.target
- apacherunning
- nginxrunning
- litespeedrunning
- cpanelrunning
- server-migrationsrunning
security-data.target
- csf-firewallrunning
- ssl-tlsrunning
- dnsrunning
- mysqlrunning
- email-servicesrunning
- rcarunning
- waf-conceptslearning
cloud.target
- aws-ec2learning
- aws-cloudwatchlearning
- aws-snslearning
- azure-essentialslearning
AWS & infrastructure projects
EC2 monitoring & CloudWatch alarms
Configure an EC2 environment, monitor CPU utilisation, set up CloudWatch alarms and explore SNS email notifications.
- EC2 instanceCPUUtilization
- CloudWatchmetric, 5-min period
- Alarmthreshold breached
- SNS topicops-alerts
- Emailsubscriber notified
# the same alarm from the CLI (placeholders in CAPS) aws cloudwatch put-metric-alarm \ --alarm-name ec2-cpu-high \ --namespace AWS/EC2 --metric-name CPUUtilization \ --dimensions Name=InstanceId,Value=INSTANCE_ID \ --statistic Average --period 300 --evaluation-periods 2 \ --threshold THRESHOLD --comparison-operator GreaterThanThreshold \ --alarm-actions arn:aws:sns:REGION:ACCOUNT_ID:ops-alerts
Linux server administration
Practice service health checks, system logs, resource troubleshooting and operational diagnostics in Linux environments.
# first 60 seconds on a server
systemctl --failed
journalctl -p err -b --no-pager | tail -20
uptime; free -m; df -hT
ss -tulpn
Web security & incident analysis
Investigate web server errors, examine logs, understand WAF protections and document root cause and recovery steps.
# RCA outline
Summary what users saw
Impact who and for how long
Timeline detection → fix
Root cause the actual failure
Fix what changed
Prevention what stops a repeat
Key Achievements & Technical Solutions
A closer look at practical troubleshooting workflows for Linux hosting, production incidents, security and service reliability.
High server load and MySQL bottlenecks
Investigate CPU, memory, I/O and long-running database queries to isolate performance constraints.
View Case Study ↗ MySQL case ↗HTTP 502/503 and backend recovery
Trace web-server errors through service health, logs, PHP/application backends and resource limits.
View Case Study ↗Suspicious traffic and WAF investigations
Review traffic patterns, security events and firewall controls while preserving legitimate access.
View Case Study ↗Domain resolution and HTTPS failures
Separate DNS delegation, record, cache and certificate-chain issues with evidence-based checks.
View DNS Case ↗ View TLS Case ↗Email delivery and authentication
Use mail logs, queues, SMTP responses and SPF/DKIM/DMARC checks to trace delivery problems.
View Case Study ↗Recovery, migration and root cause analysis
Plan safe changes, validate service recovery, document contributing factors and reduce repeat incidents.
Migration case ↗ RCA case ↗Explore all technical case studies ↗
These case studies describe diagnostic approaches and resolution strategies; they are not claims of specific completed incidents or measured results unless separately verified.
How I troubleshoot
Four common hosting incidents and the commands I reach for first.
Paths follow RHEL-style layouts and example.com stands in for the real domain.
# CPU, memory or I/O spike uptime; nproc # load average vs. core count top -b -n1 -o %CPU | head -15 # top CPU consumers ps aux --sort=-%mem | head -10 # top memory consumers free -m; vmstat 1 5 # swap activity, run queue iostat -x 1 3 # disk saturation (sysstat) ss -s # socket totals, connection floods tail -n 500 /var/log/httpd/access_log | awk '{print $1}' | sort | uniq -c | sort -rn | head
What I look for
- Sustained load above the core count
- Swap in/out or high iowait
- One account or process dominating
- A single IP hammering login or XML-RPC endpoints
# website returning 500 / 502 / 503 systemctl status httpd --no-pager journalctl -u httpd --since "30 min ago" --no-pager tail -n 100 /var/log/httpd/error_log apachectl configtest # syntax check before any reload df -h; df -i # full disk or exhausted inodes namei -l /path/to/docroot/index.php # permissions along the whole path ausearch -m avc -ts recent # SELinux denials
What I look for
- Config syntax errors after a change
- PHP fatal errors in the error log
- Ownership and permission problems
- MaxRequestWorkers reached under load
- Disk or inode exhaustion, SELinux denials
# site not resolving, or certificate warning dig +short A example.com dig +short NS example.com dig +trace example.com # follow delegation from the root dig @8.8.8.8 +short A example.com # compare with another resolver openssl s_client -connect example.com:443 -servername example.com </dev/null 2>/dev/null \ | openssl x509 -noout -subject -issuer -dates curl -sI https://example.com | head -5
What I look for
- Nameservers at the registrar not matching the zone
- Old records still cached (TTL)
- Expired certificate or wrong hostname on it
- Missing intermediate certificate
- Redirect loops
# mail not delivered, or landing in spam dig +short MX example.com dig +short TXT example.com # SPF dig +short TXT default._domainkey.example.com # DKIM (selector varies) dig +short TXT _dmarc.example.com exim -bpc # messages waiting in the queue exim -bp | head -20 tail -f /var/log/exim_mainlog
What I look for
- Missing or wrong SPF, DKIM or DMARC records
- Queue build-up on the server
- Remote rejections: blocklists, reverse DNS
- Authentication failures on a mailbox
Certifications & learning
Issued Oct 2026
Red Hat Certified System Administrator (RHCSA) (EX200) Cert Prep
LinkedIn Learning
Learning focused on system administration and Red Hat Enterprise Linux (RHEL).
View on LinkedIn ↗Issued Oct 2026
Microsoft Azure Essentials by Microsoft Press
LinkedIn Learning
Learning focused on Microsoft Azure cloud concepts and services.
View on LinkedIn ↗Let's connect.
Interested in Linux administration, infrastructure engineering, DevOps and cloud operations.