RV340W - Some Computers Connected to LAN but not Internet

[devon12345678]

I am running an RV340W for a SMB networking application. I have about 20 computers connected to this router via ethernet and a handful of switches. Right now, most computers are working completely fine while some are able to connect to the network but unable to connect to internet.

All of the computers are on static IP addresses.

When I check the TCP/IPv4 properties on one of the problem computers, everything matches the DHCP Server I set up in the RV340W router. The IP address is within the Range Start and Range End. The DNS server is set to dns-server-static and the Static DNS1 and DNS2 match what is in the TCP/IPv4 properties.  

My DHCP Server is set to 192.168.3.1-192.168.3.255. I have a problem computer at 192.168.3.126 but a good computer at 192.168.3.132

When I check the VLAN settings in the RV340W, I don't see much I could change other than the Mask or the Inter-VLAN Routing. 

Any ideas on what else I could check to see what's going on?

[Flavio Miranda]

Hi

   yeah, this means something.  Do you have more than one exit to internet? By any chance the PC has more than one gateway?

[devon12345678]

There is only one exit to the internet. I attached a high level diagram of the network.

 

[devon12345678]

New clue to this puzzle:

When I'm on a bad computer (192.168.X.186), I can access the LAN network (shared drives, see other computers). I can also ping a good computer (192.168.X.134). 

When I'm on the good computer, I cannot ping 192.168.X.186. Cisco router is also unable to ping the bad computer. 

Does this peculiarity point to any solutions?

[Flavio Miranda]

Even more weird.   I suspect about mask or gateway but you tell me.  I am running out of idea already.

[devon12345678]

What do you mean when you say you suspect the mask or gateway?

Thank you for your time and for helping me out with this problem. I am running out of ideas myself, I am pretty stumped by this problem. 

[Flavio Miranda]

"What do you mean when you say you suspect the mask or gateway?"

 This behavior you´ve seen happens sometimes if you have some mask inconsistency. Example, the network is 192.168.3.0/24 but then the gateway is /25.   But, it is a long shot. At this point, you probably already over look everything.

[devon12345678]

The pinging issue was just a firewall issue. Solved that, but no resolution to no internet connection  

[Rich R]

If the PC is set to automatic = use DHCP.

If the PC is configured statically (not automatic) = NOT DHCP.

So having said you ARE using DHCP you've admitted you actually are not!

That's almost definitely why you're having problems due to duplicate IP addresses.

If you want to reserve IPs that should be done on the DHCP server and the PCs with reserved IPs should get the reserved IP from the DHCP server.

Otherwise you need to choose a block for static IPs and exclude that block from the DHCP pool.

But allowing static IPs is dangerous because then anybody can try to use a static and cause a conflict for others.

[devon12345678]

Yes, I have learned through troubleshooting this that I did indeed contradict myself in my original post. While troubleshooting, I shrunk the DHCP range down to 192.168.X.26-192.168.X.120 on VLAN1 which is where both the wired and wireless devices connect. I have done IP scans and also manually checked the IP addresses of the problem computers using the ipconfig command and have not found any IP address conflicts, but unfortunately the problem has persisted.

One thing that is still puzzling me is that when I set the problem computers to obtain IP address automatically, they are able to pull an IP address outside of the range I specified. 

One thing all the problem computers have in common is that they are Windows 7 computers. 

Things I've tried so far:

TCP/IP Reset (netsh int ip reset resetlog.txt) along with winsock reset on elevated CMD

Disabling IPv6

Triple-checking that both IPv4 and 6 are set to automatically retrieve IP/DNS

Triple-checking that DCHP client service is active

Manually setting DNS server to 8.8.8.8
Turning off/on router for 5 minutes

Disabling firewall

Uninstall/reinstalling the network card driver

Flush+register DNS, then ipconfig /release+ /renew on elevated CMD, which is stuck at /release with "An error occurred while releasing interface Loopback Pseudo-Interface 1 : The system cannot find the file specified." error.