Windows 7 Default static gateway IP keep disapearing

[DIYguy]

A variation on similar problems others have had.
I have had my network running for a couple years without problems. I'm using Comcast Business Class broadband with a static IP and a Linksys E3000 router for a home business network. Four wired computers and the rest are wireless for a total of (22) nodes. All set up with static IPs.
Over the weekend I tried to add a wireless security camera and part of the installation required accessing my router. When I attempted to login to the router I found my password access no longer worked. I ended up having to do a factory default restore. I have printouts of my original setting so I recreated the original settings for my WAN side and LAN side, set up for static and set the range for DHCP IP's. Two of the wired computers are working as they should, the wireless seem to be working. Two wired computers are not.
The problem is.....When I set up the IP configuration as static in my main computer and close the system manager the computer sees the network and internet for about 30 to 60 seconds and then drops the default gateway IP address. Go back in and check the settings and the gateway address field is blank, all the rest of the settings are intact. Repeat, good for 30 to 60 and goes blank again. Checked ipconfig/all, did the ipconfig/release, uninstalled the network card and let the system reinstall, same problem. Tried giving up on static setting for the moment and thought the system was working but then is started dropping the internet and network again. I'm running ot of options.
The two computers that DON'T work are my main server that runs the accounting software that is synced with the internet ecommerce website and the shipping department funning UPS Worldship and Quantum view. Without these two computers I'm out of business! I have orders to fill and can't! The only other think I can think of is I used Cisco Connect to do the initial configuration for the router and ran it from the main computer. Wondering if is set something in the registry that is trying to override the static setting?
Even a friend of mine that is in charge of network IT has been unsuccessful with this.
I need help FAST!

 

[patcooke]

We need to examine your ipconfig output.

 

[DIYguy]

I did a copy of the ipconfig/all report but I'm hesitant to post that info on the internet for security reasons.
I spent yesterday afternoon continuing to work on the disappearing gateway IP and tried power cycling the business gateway, switch and router again. Before cycling I noticed what looked like an extreme amount of activity in the switch and router, all the port lights were flashing quickly. Power cycled, business gateway, switch and router and repowered gateway and then router, no switch. Activity seemed normal, waited a short while then powered the switch again. Switch went nuts again. I'm thinking either bad switch or collisions? I completely disconnected the switch, as the two critical machines are connected directly to the router. Reset the IP settings and gateway in the two critical machines with nothing else...e connected. Both machines connected as they should, network and internet. After two hours as the only machines on the router they were still holding their settings.
Did some experimenting with reconnecting select pieces of equipment and the two critical machines dropped the gateway settings again. Disconnected everything except the two machines, reset and they are working again.
At this time I am now highly suspicious that a 2nd switch that was added last Saturday could be the culprit. After MANY years of service my old HP 2100 LaserJet parallel printer started acting up so I replaced it with a new HP P3015DN network printer. Over the weekend I added a switch in my office so I could connect both office printers to the network. The 2nd switch is connected to the line that is connected to the first switch. The first switch is connected to the router using a crossover cable, I did not use a crossover cable between the wall plate and the 2nd switch. I thought the new switch's were auto sensing and did not require crossover?
Could two switches on the same circuit be causing collisions and could those collisions be causing the gateway IP to disappear?

Had a strange phone call from my wife. My reply to this thread showed up on my wife's Facebook page and received replies there. I never new this forum had that option ???

 

[DIYguy]

Thought I would post an update. Did some more investigating and I think I have more info. What the two critical machines that kept loosing their gateway IP had in common was they were both connected to the HP P3015N network printer. The installation software that comes with the printer was run on both computers and configured as "Network" printer. Installation worked just fine accepting default settings during the installation, the network found the printer and both computers where able to print to the HP printer. I believe that was about the time the computers kept loosing their Gateway IP and internet connections. When I disconnected the switch connected to the printers it wasn't the switch causing issues it was the HP printer. Did some digging into the settings and the software configured the printer using IPv6 settings. My network is set up with (26) different nodes all with static IPv4 IP addresses. I am firmly convinced that the IPv6 settings were conflicting with my existing IPv4 settings.
Has anyone encountered a similar problem with IPv6 and IPv4 conflicts?

 

[patcooke]

IPv6 is not currently required for mainstream operations and has been identified as causing some problems. Unless you know you have some specific requirement it is recommended that it be disabled.