Router cannot see the client


#1

my router is connected to a switch which is then connected by fiber to a remote switch. I have a device I am trying to forward to on the remote switch. I can ping it while on their network but my router cannot see it in the client view. I did a port forwarding to the ip of the device but cannot connect from the outside world, am I missing something on how to pull this off?


#2

Just want to make sure we’re talking switches and not routers. And then, are these managed switches? Or at least, is the remote one a managed switch? Are vLANs involved?


#3

Well, both. I am looking at my router client list and cannot see a device that is down the line. I can ping it from the network but not see it in the client list of connected devices. The router is connected to a switch and one of the ports of that switch is converted to fiber and connected into the gbic of the 2nd switch. this is an onsite cob together of a network and i came in and and replaced the router so we could get some port forwarding done. the switches are different brands and unmanaged.


#4

no vlans


#5

How or where does a device at the far end gets it IP? What is the private IP of the far-end device and the router?

If the network is flat - meaning that are devices are using the same LAN segment and subnets with a common DNS, DHCP server and gateway, then any and all devices attached to same should be able to “see one another”.

If the far-end device has an IP that is not of the same group as the router LAN segment and not within the subnet mask, it may not show as a client and you may not be able to forward to it.


#6

Thanks so much for your help and patience, i am an old phone guy learning new tricks.

I am assuming my router is giving out the ip addresses. The router is the basic 192.168.1.1, the end device I cannot see in my client list is 192.168.1.112, yes i believe this would be considered flat. I can check the subnet mask of the end device.


#7

You also need to check the end device to see if it is set for DHCP or if statically set.

Please check and insure that the router is indeed the DHCP server for the network.

While i don’t know that it will help, you might reboot the switches as it certainly won’t break anything (assumes they are truly dumb).

If needed, disconnect the router or disable the embedded DHCP server and connect a device set to receive DHCP and see if it gets a new IP. Do so at both the near and far end. If it gets an IP, then look for the other server and disable the function if appropriate. Check to see what gateway and subnet is being issued and then insure that the router conforms to same on the LAN side. If you leave the other server enabled, then disable the router DHCP server aspect.

If no address is issued, then reconnect the router and see if the device is issued an IP from the router’s pool of IP, again at both ends. If so, then see if it shows in the router client list or ARP list. If the device gets an IP at the router end, but not at the far end, then there is something else in the network at play.

if the router does indeed issue the address, then go back to the original end device and copy down the MAC address and make a reservation for it in the router and assign the desired IP. Then change the original device to DHCP and see if it picks up the address you assigned.

What make & model of router?


#8

Thank you for the outstanding troubleshooting info. The router is a GWN7000. I will be to site hopefully later this week and will go through those steps. Thanks again