Servers, networks and phone systems that stay up.
I'm Mohammad Abu Syed, an infrastructure engineer with 15+ years running production Linux fleets, IP networks, clouds and carrier-grade VoIP for telcos, cloud providers and businesses, and I sell my own multi-tenant PBX and AI voice agent platform through AsteriskBD. I've led infrastructure as a CTO and Head of Infrastructure, and now work directly with clients.
in production Linux, networking and VoIP operations
from 104 client reviews on Freelancer.com since 2012 · 98% on budget
uptime, up from 97.5%, by removing single points of failure
maintenance windows cut for a high-capacity telco platform
Teams and clients in Singapore · Malaysia · United States · Italy · Bangladesh
Services
One engineer across the whole stack
Most problems cross boundaries: a dropped call is often a network or server problem, and a slow app is often storage. I work across all of it, so nothing falls between vendors.
VoIP, PBX & call centres
Asterisk PBX, Kamailio SIP proxies, VICIdial call centres, SIP trunks, cloud telephony and AI voice agents, built for live call load.
Linux servers & performance
Builds, tuning, troubleshooting and Tier-3 support for RHEL, Ubuntu and Debian fleets, from one VPS to hundreds of servers.
Networking
Cisco and MikroTik routing and switching, VLAN segmentation, site-to-site VPN, firewalls, NAT, DNS and QoS for voice.
Cloud & virtualisation
AWS, OpenStack private clouds, oVirt/RHEV and Virtuozzo hyper-converged platforms. Large VM and container migrations.
Kubernetes, CI/CD & automation
Containerising apps, Kubernetes clusters, Helm, CI/CD pipelines and Ansible, so deployments are repeatable and auditable.
Storage, databases & DR
GlusterFS and software-defined storage, MySQL/MariaDB, MongoDB and Oracle, plus backups that are tested and a real disaster-recovery plan.
Security & hardening
Server and network hardening, security audits, vulnerability fixes and incident response, backed by an MSc in Cyber Security.
Monitoring & IoT data
Alerts before users notice. Grafana and InfluxDB dashboards, Nagios and CloudWatch, plus Node-RED and MQTT pipelines for IoT and energy data.
Mail servers & business apps
Self-hosted Mailcow with SPF, DKIM and DMARC that lands in the inbox, plus n8n, GLPI and other business apps run properly.
White-label SIP apps for business phone systemsYour brand
Give your business phone system its own app, with your name, logo and colours, published under your account on the App Store and Google Play. I build SIP softphones for mobile and desktop that connect to your PBX (Asterisk, FreePBX, Kamailio or your own platform), so staff can use their office extension anywhere. VoIP providers and resellers get a new brand per customer from one codebase, and the apps plug straight into the Saynth multi-tenant PBX.
- Your logo, colours, app name & icons
- Auto-provisioning from your PBX
- HD calling, hold, transfer, DND
- Incoming calls when the phone sleeps
- SMS / MMS per business number
- Voicemail with transcripts
- CRM screen pop on incoming calls
- Speed dial & BLF keys
- Office extension on mobile & desktop
- App Store & Play Store publishing
My products
My own PBX and AI voice platforms, ready to deploy
Besides client projects, I build and run my own telecom products under AsteriskBD. Buy them, host them with me, or white-label them as your own.
Saynth Multi-Tenant PBX
Launch your own branded cloud PBX business. Fully white-label, with each tenant billed and branded separately.
- Unlimited tenants, multi-tier resellers
- Auto-provisioning for Yealink, Grandstream, Polycom, Fanvil
- Per-tenant billing, features and branding
- Branded softphone apps for your customers
- REST API for BSS/OSS
AI Voice Agent
An AI receptionist and support agent that answers every call 24/7, in natural language, and hands off to a human when needed.
- Multi-language voice
- Human handoff with context
- CRM & ticketing integration
- Sentiment analysis & analytics dashboard
Sales AI Ops
Outbound AI calling that qualifies leads, books appointments and follows up, so your sales team only talks to warm prospects.
- Lead scoring & appointment booking
- 12 CRM integrations: Salesforce, HubSpot, Zoho, Pipedrive and more
- Call recording & conversation insights
- A/B testing for call scripts
Telco AI Gateway
Add AI voice to any existing SIP trunk or switch without replacing your network.
- SIP-to-AI gateway
- Works with multiple AI providers
- Load balancing & failover
- CDRs & operations dashboard
Cloud PBX Hosting
A fully managed business phone system, so you never manage a PBX server again.
- From $12/month, no setup fee
- 99.9% uptime SLA, daily backups
- IVR, queues, recording, WebRTC softphone
- Free migration from your current PBX
IP PBX & Call Centre
Asterisk, FreePBX, Issabel and VICIdial systems built for your business and run for you.
- Single office to multi-site
- Custom IVRs, call flows & integrations
- Inbound & outbound call centres
- Softphones & mobile apps
Client reviews
104 reviews. 4.9 out of 5.
Verified reviews from Freelancer.com clients in 28 countries since 2012. A selection, lightly trimmed:
“Yes, always again, it was really good work done. I will continue with Mohammad.”
“Mohammad made a dialplan integration for Asterisk for us to send data to a URL. The work was done excellently. We will gladly come back to him for future projects.”
“He completed the task ahead of schedule and was very honest about the time spent… very helpful, knowledgeable, understanding and quick to respond when needed.”
“Great developer. I’ve received more than I asked. Highly recommended!”
“There is no doubt that Mohammad is an expert… a VPN between a travelling router and my home network, successfully done using 2 MikroTik routers and a Raspberry Pi.”
“Highly responsive. Highly educated and very adaptive to every scenario… If you’re interested in an individual that’s dependable and timely with their commitments, he’s your guy.”
Ways to work together
Clear scope. Fixed price. No surprises.
Every project starts with a free call and a written quote within 24 hours. Custom work is welcome.
Infrastructure audit
Fixed price
- Servers, network & security review
- Backup and DR check
- Risks ranked by urgency
- Written report + call
VoIP / call-centre setup
Fixed price
- Asterisk, Kamailio or VICIdial
- SIP trunks & DIDs
- QoS & security hardening
- Call-quality monitoring
White-label SIP phone app
Fixed price per brand
- Your brand on Android, iOS, desktop
- Connected to your business PBX
- Calls, SMS, voicemail
- Store publishing under your account
Platform build or migration
Fixed price
- Cloud, Kubernetes or private cloud
- Migration from legacy servers
- CI/CD & Ansible automation
- Runbook + handover call
Monthly care
Monthly retainer
- Patching & security updates
- Backup & restore tests
- Monitoring & priority support
- Monthly report
Emergency fix
Fixed price per incident
- Server, network or PBX down
- Calls dropping or one-way audio
- Root cause found, not just patched
- Short written incident report
Experience
Where I've done this before
Telcos, cloud providers, call centres, universities and energy companies across five countries.
Chief Technology Officer
2012 – presentTechnical direction and hands-on delivery of Linux, network and Asterisk voice infrastructure for client deployments, from server builds to Tier-3 support.
Head of Infrastructure
2024 – 2026Moved a smart-energy monitoring platform onto Docker and Kubernetes with InfluxDB, Grafana, Node-RED and MQTT. Designed secure IoT networks on MikroTik and built CI/CD and Ansible automation.
Chief Information Officer
2024Ran company IT for availability and security, integrated VoIP with core infrastructure, and moved the team from reactive fixes to proactive monitoring.
Technical Engineer, Cloud Deployment & Operations
2022 – 2024Designed and deployed public and hybrid clouds and hyper-converged infrastructure for MSPs, ISPs and cloud service providers.
Head of IT & Infrastructure Operations
2019 – 2022Led AWS, Linux, network and SIP engineers for a high-capacity cloud phone platform. Cut maintenance downtime from 2 hours to 30 minutes and tuned Linux performance by up to 30%.
Earlier: VICIdial and Asterisk administration for a US call centre · OpenStack private cloud and 236 TB GlusterFS for Dhaka International University · senior systems engineer leading a five-person team on ~80 Linux/Unix systems at Mesh Technologies · VoIP switching operations at Volt9 Networks (US).
Certifications & education
Verified skills
Certifications earned across Red Hat, AWS, Cisco and Virtuozzo, with a master's degree in Cyber Security.
Red Hat certifications can be verified with ID 170-290-290 at rhtapps.redhat.com/verify. AWS and Cisco badges are on Credly.
How it works
From first call to handover
You always know what's happening and what it costs.
Free call
20 minutes to understand your setup, the problem and what "done" means for you.
Written quote
Scope, timeline and a fixed price within 24 hours. No hourly meter running.
Build & test
Read-only checks first. Nothing changes in production without your approval.
Handover
Runbook, architecture notes, credentials returned and a walkthrough call. You own everything.
FAQ
Common questions
Where are you based, and which time zones do you cover?
I'm based in Dhaka, Bangladesh (GMT+6) and have worked with teams in Singapore, Malaysia, Italy and the United States. I can overlap with Asian, European and US business hours.
Do I need to give you root access?
Only for the duration of the project, and only where needed. At handover you rotate the credentials, and I keep nothing.
Can you fix something that's broken right now?
Yes. Emergency troubleshooting is available for servers, networks, call quality and databases. Message me with what's happening and I'll tell you quickly whether I can help.
Our calls drop or sound bad. Is that the PBX or the network?
Often the network: NAT, SIP ALG, missing QoS or jitter. Sometimes it's the server or the trunk. I've run both sides for telcos, so I'll find which one it is.
Do you sell a ready-made PBX or AI voice agent?
Yes. Through my company AsteriskBD I offer the Saynth multi-tenant PBX (white-label for telcos, ISPs and resellers), AI voice agents, Sales AI Ops, a Telco AI gateway and managed PBX hosting from $12/month. You can buy, host or white-label them. Details are at asteriskbd.com.
Can the app carry our brand, and can we resell it?
Yes. The app is published under your developer accounts with your name, logo and colours, and it connects to your PBX. VoIP providers and resellers use it to give each of their customers a branded app. You own the store listings.
Should we move to Kubernetes or the cloud at all?
Not always. For a few small apps, a well-run server is often cheaper and simpler. I'll tell you honestly on the first call.
How do payments work?
Fixed-price projects are usually split 50% upfront and 50% on handover. You can also hire me through Freelancer.com (where I've worked since 2012) or Upwork if you prefer their payment protection.
Tell me what you're running, or what's broken.
Send a short message with your setup and goal. You'll get a reply within 24 hours, and a fixed-price quote if it's a fit.