Ok, I manage a very small network in my wife's vet clinic. This network was working correctly for me for over a year with no issues...It is very, very basic. I replaced a wireless router, and now It is completely futzored!
Here's what I have:
1 Actiontec DSL Modem (with wi fi and a 4 port switch built in)
connected via cat5 to to the internet port on
1 Linksys BEFSR81.
Ok, now the Actiontec modem provides internet access.
Connected to the linksys BEFSR81 is:
1 Netgear Wireless router (new, working fine)
3 windows workstations (1 acts as an internal server, the others are merely workstations)
1 Canon printer
The ideal situation is that any computers connecting to the network either directly plugged into the BEFSR81 or via wi fi (through the Netgear router), should be able to see the internal server AND they should be able to access the internet. This is not happening.
The machines connected to the BEFSR81 can see the internal server, but have no internet access.
Any machine that connects directly to the Actiontec modem (via its own wireless) can see the internet, but not the BEFSR81 or anything connected to it.
I am suspecting a problem with the communication between the BEFSR81 and the Actiontec, but I can't seem to confirm. I have tried just about every possible configuration of DHCP, CNS, UPnP that I can on both of these devices. I am at wits end. Unfortunately, it does have to be fixed. The server has equipment tied to it that use the internet to file test results. If we can't use the equipment like that, we have to send our tests out, and that is much more expensive for us. So each test that goes out is money I am losing the clinic.
The lab machines only need internet access. There is no configuration (they can be remotely configured by the company we lease them from), and they needed 0 setup when installed. but they can't see the internet right now.
I will of course monitor the thread closely and answer any questions, but basically, I am totally lost now. Any ideas would be appreciated, and may move me forward.
Hmm ... So if you have DHCP off on linksys and are only using its switchports with Actiontec plugged into one of the switchports itself, any clients connected to the switchport should just be able to get IP Address via DHCP from Actiontec. If this does not work it is time to look deeper and see what the MACs being learnt are (looking at ARP cache on the hosts) and possibly take sniffer captures.
As a starting point I would suggest you disconnect the Netgear for the time being and bring the configuration on devices back to the original working config (NAT/DHCP on Linksys). Next connect the Actiontec cable to Linksys WAN port and verify the WAN port is getting an IP Address from Actiontec. Once this is confirmed connect a laptop to Linksys switchport and verify it gets an IP Address from Linksys. If that works then from this laptop ping the Actiontec IP Address and after this is a success then try browsing for internet. If internet browsing does not work verify DNS. If you are able to make all of this work then Netgear can be introduced back into the equation to see if connectivity remains as desired.