DSL-2640R ADSL/Wireless Router Setup

Question

We have a router operating in front of one computer which is separate from the rest of the network. Most of the time it operates fine but we find sometimes it loses connectivity, both internet connectivity from the machine and access to the machine remotely. This is not acceptable as the machine is operating rather critical processes and ideally it should be available 100% of the time.

I cannot determine if the fault lies with Windows, the router or the network.

ADSL Connection Type                        PPPoE/PPPoA
Firmware                                    v1.06
Port forwarding                             None
DNS                                         Auto
Firewall                                    None
DMZ                                         192.168.1.2

If anyone has any ideas it would be appreciated

Answer 1

First disconnect everything. Find your NID (network interface device, aka DMARC) and plug the modem into the customer side (you likely won't have access to the ILEC side) and then connect a laptop to it and set it to ping with a 200 ms interval to your ISPs primary DNS server overnight (unless it is in a location where this is not possible, then you will just have to sit with it for a few hours to see if there is any visible loss on the circuit). This test will let you know if your ISP is the problem or if it is on your end. If you find it is the ISP, call them up, tell them what you did and send them the ping results and they will do the rest.

If you find that there are no issues there, connect it back up where it was before, with only your laptop again, and perform the same ping test. This will determine if your IW is to blame. If this test fails, then you need to replace the cabling between the modem and you NID.

If you find there is no issue there, add you router back into the equation and run the ping test again. You should notice a pattern here. Basically start with the fewest variables and rebuild your network until the issue presents itself. At that point you know what is causing the issue. If you do find it is on your network, it may be prudent to try a TCPDUMP to watch the traffic and see what is happening to it when you experience drops. You can often narrow it down to a specific interface that way.