As taken from a recent email conversation with a customer:
There are several issues that can cause internet connectivity issues. If Verizon says that their service is running smoothly, then typically they are correct – although I have seen cases where the ISP states that nothing is wrong with their service and there really is an issue.
As I’m sure you are aware, any downtime in your ability to use the Internet leads to productivity loss and costs you money. It would be well worth your time to contract with me to straighten out your network. For instance, when we first met you were having issues with Outlook Express – and the problem was that you had well over 13,000 emails in your inbox causing OE to choke.
One other very important point to remember is that you really should have a backup system in place. If your pc’s go down, you risk losing your data which is far more important than the hardware itself.
Here are some possible things causing your issue:
Based on the huge number of spam emails that I’ve seen flow through your email system, it is very likely that one or more computers on your internal office network are infected.
What typically happens is a user opens an email attachment that is untrusted or visits an untrusted website through Internet Explorer and gets exploited. Usually the exploit does not crash the computer, it loads software that runs in the background spewing SPAM out.
Potentially some of these exploits could also be sending information stored on your computers such as client information, etc. Once a machine is exploited all bets are off.
SPAMMers don’t have warehouses full of computers. They use exploited PC’s – zombies – to send out the spam. That is part of why it is so profitable.
Problem: Zombies are uploading/downloading on your network consuming your bandwidth and causing you to think your Internet service is down.
Resolution: All pc’s on your network should be thoroughly checked out, possibly re-imaged, and practices put in place to avoid the problem in the future.
Email and Spam
This issue is closely related to “Zombies”. Your users receive an inordinate amount of email and much of it is spam. This consumes bandwidth and can cause what appear to be “temporary outages” in your Internet connection.
Problem: Too much inbound spam.
Resolution: Migrate to Google’s email service as recommended several times.
Users abusing Network
This happens much more frequently now. Users tend to want to view MySpace.com or Youtube.com on company time and using up company resources. Video and audio consumes a lot of bandwidth, which can cripple your legitimate traffic.
Resolution: Setup a system to restrict certain domains and websites plus enforce a company policy that prohibits such usage.
Hardware can begin to intermittently fail. There is always a possibility that your router or modem is occasionally having an issue.
Resolution: Replace faulty hardware.