DNS not responding or not found

[tonynahon]

Hello Everyone: I am involved with a community organization where there are 6-7 Windows PCs and 2 Mac computers attached via Ethernet to the local area network. In the last week or so we have had a problem on both the PCs and Mac computers, where internet connectivity fails with error messages referring to DNS Server not found or not responding. The problem only affects computers using Ethernet as their network connection; computers using WiFi for Internet connectivity are OK.

Resetting the Shaw Modem/Router (power off/on) resolves the problem until the next time it happens. We did experience a lengthy power failure, but that was 3 weeks ago. I haven't called Shaw yet, but that is my next move, unless anyone has any ideas on any possible solutions that I would be able to apply.

Regards,
Tony N

[mdk]

@tonynahon -- The problem only affects computers using Ethernet ... omputers using WiFi for Internet connectivity are OK.

Are the WiFi-using devices connecting to the same cable-modem as the Ethernet-connected computers are connecting?

Are the WiFi-using devices connecting to some other WiFi network (ShawOpen, ShawGo, Freedom Mobile, Shaw Mobile) ?

What "private" IP-addresses are being used by each of your wired/WiFi devices, e.g., "10.0.0.2" and "10.0.0.3" and "10.0.0.4", and so on?

Of course, you might have a "hardware" problem with Ethernet adapters inside the cable-modem, rather than a "software" or a "connectivity" problem.

If you logon to the web-interface inside the cable-modem, can you view the list of connected devices, and to view the IP-addresses assigned to each of the connected devices?

When you contact Shaw, ask them to remotely logon to your cable-modem, so that they can check it out. Any "out-of-spec" cable-modem can cause issues.

[tonynahon]

Hi mdk: Thank you for responding to my question about internet connectivity problems. Your questions are all good; unfortunately, I am not at the site at the moment and I don't have all the answers. However, I have a couple of comments, as follows:

• The WiFi-using devices eventually connect to the same cable-modem as the Ethernet-connected devices, but not directly - there is at least one switch/router which distributes traffic from the modem to devices on the LAN.
• Are the WiFi-using devices connecting to some other WiFi network (ShawOpen, ShawGo, Freedom Mobile, Shaw Mobile)? Good question. I believe we do have an in-house ShawOpen service - so would that mean that they could be bypassing the LAN infrastructure altogether when they connect to WiFi?

Apparently someone else is following up with Shaw, so hopefully they will be able to be able to identify what's going on. In the meantime, thank you for your insights and suggestions.

Regards,

Tony N.

[mdk]

@tonynahon -- 

1. The WiFi-using devices eventually connect to the same cable-modem as the Ethernet-connected devices, but not directly - there is at least one switch/router which distributes traffic from the modem to devices on the LAN.

I am not sure of your configuration. 

You say that your WiFi devices connect nicely, either to any WiFi-capability that router "switch/router" may possibly have, or the WiFi devices connect nicely to the WiFi-capability of the Shaw cable-modem.

A "switch" just acts like an electrical extension cord -- all traffic just passes through it. But, a router does more work -- compare to the clerk at the fast-food restaurant -- they take your order, pass it to the "fries" worker, and pass it to the "burgers" worker, and gather your ordered items, and deliver them to you (not to another customer).  Since you indicate that your Ethernet connections are problematic, you'll have to see if that "router" is having an issue.

2. Are the WiFi-using devices connecting to some other WiFi network (ShawOpen, ShawGo, Freedom Mobile, Shaw Mobile), A&W Free WiFi? Good question. I believe we do have an in-house ShawOpen service - so would that mean that they could be bypassing the LAN infrastructure altogether when they connect to WiFi?

That is possible, but you can check each device, to see to which SSID it has connected -- either the SSID of your "private" WiFi network, or to one of those other "commercial" SSIDs. If you device has the "connect automatically" option for more than one SSID, it is possible that your device may connect to the "wrong" SSID.

[tonynahon]

Hi mdk: Thank you for your additional comments - I'll keep them in mind as we go forward with Shaw.

Regards,
Tony N.