Accessible IT over 25 Years


After 25 years in service, we have over 500 active clients, but confidentiality agreements prohibit us from releasing any client information. Some of our long-standing clients have permitted us to include them on our reference list and they will be more than happy to talk to you and provide additional references.
Thank you for taking the time to consider us as your new I.T. partner.




As a company that distributes food items across Canada and the US, it is critical that we have fast, reliable computer systems that can operate 24/7. In addition it is essential that we have access to immediate remote trouble shooting and on-site service from our IT resource supplier. All aspects of our distribution system from purchasing, payables, sales, receivables, and statistical data are reliant on our computer system. A computer crash for us means that we are essentially out of business until the problem can be rectified and what makes the task even more difficult is that we have 6 Servers and 46 workstations which 16 of them are constantly out of the office and across Canada and the U.S. but Diagnostic can access the systems and correct the problem no matter where they are located.

Diagnostic Network Technologies has provided this service to us since 1997. Diagnostic has always been there when needed and has successfully seen us through several crises over the years. Their staff from the President on down has always been courteous and extremely knowledgeable and has treated Olympic throughout the  years as priority No.1 ( or at least one of their priority No. 1 customers).

I can unequivocally state that I would highly recommend Diagnostic Network Technologies to anyone looking for a company to provide computer support whether it be software or hardware. 

Glenn Croucher


75 Green Court, Ajax, ON  L1S 6W9

905-426-5188 ext 116


DFSI_EN (3) We have been clients of Diagnostic Network Technologies since their inception 25 years ago and are very pleased to write this letter of reference.

We are a medium sized Financial Planning office and rely on Leo and his team at Diagnostic to provide us with leading edge computer technology combined with the most secure environment and virus protection available.   In our industry it is critical that our everyday operations run smoothly and that we have uninterrupted access to our internet trading platform.  Diagnostic understands our needs and our scans, updates and maintenance is completed by them after hours.

Diagnostic Network Technologies maintain, troubleshoot and administer our local area networks (LANs), servers, computer workstations, peripheral systems and software.  They provide problem-solving services to network users; perform data backups and disaster recovery operations; install, maintain, troubleshoot and upgrade server and station hardware and software.

Our computer needs have both changed and grown over the years and Leo and his team have always been there offering superior quality work, on time, and within budget targets.  We have always been impressed by their outstanding diligence and high level of technical expertise and would recommend them to any company requiring hassle-free IT.

Richard S. Price, EPC
Senior Financial Advisor
Desjardins Financial Security Investments Inc.



flogo We are proud to celebrate our 25th year in the industry.
Diane Fairbanks our tireless President having her own strong determination to learn and succeed, she has been able to not only keep the business growing through the ups and downs of the world economy, but continues to search for new and innovative products and ways to keep costs for our customers in check. The company has continued to put quality and service “FIRST” for 25 years and one of the major reasons we achieved this was through strong IT support while maintaining a reasonable IT budget.
Diagnostic Network Technologies and Leo with his team is our #1 choice for all IT needs and have trusted his dependable opinion and been pleased with all the services and hardware for over 15 years now. Our uptime of 100% has remain unchanged since day one and when very rarely have a question or need help the response is usually under 5 minutes.
Thank you Leo for contributing to our success.

Corrinne Fairbanks
Operations Manager





We are a boutique consultancy that is project oriented, with all our work being driven by time-sensitive deliverables. Diagnostic Network Technologies has supported our business since we opened over 12 years ago, and prior to that DNT had provided the IT support to the regional office within which I was a partner. Leo and his team have kept our systems up and running, and with the latest remote monitoring software they have been able to make software updates, adjust settings, and identify hardware weaknesses without having to come to our offices and disrupting our schedules. They have always been exceptionally responsive to any problems we have encountered and within minutes have been able to trouble shoot these and identify a solution. Since bringing DNT onboard, we have never had to call a client prior to a deadline and plead systems failure. Leo, thank you to you and your team for the support I have been able to rely on over the past 17 years.

Tannis Chefurka, Director






Government Relations and Information Services Publishers of the Ontario Government Information Binder©


Leo Stefanidis and his team at Diagnostic Network Technologies have helped my firm since the early 1990s. Our products – the Inside Queen’s Park newsletter, the on-line Ontario Government Information Binder and other publications on provincial government and politics – are time-sensitive and must reach our subscribers without delay.

Whenever GPMRL needed quick service, Leo and company addressed the problem immediately via remote access or an onsite visit. To see the Diagnostic operatives in action is to understand what ‘full-service’ really means. They address even third party problems with outside providers so that we do not have to deal with it.

All of our hardware, software, wiring and the entire setup in general are provided by Diagnostic as they also maintain the lowest pricing in the market since day one.

I’m still grateful to the computer trainer who recommended that we use Diagnostic. They have done us proud over a business relationship which is now headed into its second twenty years.

Thank you, Leo.

Graham Murray
G.P. Murray Research Ltd.
P.O. Box 65041
R.P.O. Chester
Toronto, ON M4K 3Z2
Tel: 416-367-3777 x 111
Fax: 416-367-3778
Publishers of Inside Queen’s Park

  Faith Nesdoly

I have known Leo for almost 15 years – from the time I was a partner in a small consulting firm to now, as a sole practitioner in my own company. He and his staff have consistently provided excellent products, services and support. Leo is a firm believer in ‘doing it right’ and his recommendations are always backed up with solid rationale. If you are reviewing options at different price points, you will understand what you are getting (or not) for each option.

When my husband and I moved to Germany in 2007, Leo set me up with a home system that served me well until this winter. When it was apparent that I needed to upgrade, I emailed Leo for his advice and over the course of a week, we determined what I required to best suite my needs. I ordered a new laptop from him and during a short trip to Canada a couple of weeks later, I was able to receive it, fully set-up and customized. Back at my home office, Leo helped me remotely with transferring files, setting up my email, etc. I had absolutely no downtime and the transition was seamless. Since most of my clients are in Canada and I work remotely, this is a top priority for me.

Why do I recommend Leo and Diagnostic Network Technologies?

  • whether you are big or small, every client is an important client
  • excellent response time and problem solving
  • enables/fosters an understanding of what the system can do for you
  • provides excellent support, products and services

Faith Nesdoly