Can't access device on LAN by hostname

[den75]

Hi,> I get a DNS error when I try to access a device on my local network with RT-AC66U router with the hostname. I can get them with the IP and I also can't ping the hostname. Any ideas what is wrong?

 

[ColinTaylor]

Is the target device a DHCP client? It needs to be to register its name with the routers DNS server.

The PC that is giving you the DNS error, what DNS server is it using? It should be the router's IP address. DNS Filtering will also stop name resolution working for your LAN devices.

What do you get when you do an nslookup on the device? i.e.,

C:\>nslookup zen
Server:  router.asus.com
Address:  192.168.1.1

Name:    zen
Address:  192.168.1.55

P.S. Ping works in a "Windows" network because it uses NetBIOS name resolution in preference to DNS.
Edit: Just re-read your post about ping not working.

 

[den75]

This

 

[ColinTaylor]

Are the target devices DHCP clients?
Does it effect all clients on your network?
Are you using DNS Filter?
What kind of devices are they? PC's, printers, etc.

Edit: I don't know whether DNS Filtering is in the stock firmware, I know it's in Merlin's (you haven't said what firmware you're using).

 

[den75]

Yes, they are DHCP. I only have this one device. It's an aquarium controller and access it's dashboard to make programming changes etc. Don't think I'm using a DNS filter, where would I check?

 

[den75]

I was always able to access it via hostname. This started when I changed out the router to the ASUS

 

[ColinTaylor]

If you go into the router's GUI can you see the device in the "Network Map" > "Client List"?

What name does it have?

 

[den75]

Nope, don't see it. It's plugged into a wireless bridge if that matters, but like I said, it worked before the upgrade to the ASUS

 

[ColinTaylor]

Ah. Wireless bridges can be troublesome between different manufacturers.

Just to confirm that it's connecting to the router properly, can you look at System Log > General Log. Turn off the aquarium device, wait a few seconds and turn it back on.

Refresh the log and you should be able to see the device create a DHCP connection and its IP address.

Can you confirm that please?

 

[den75]

Got an IP of 192.168.1.139

 

[ColinTaylor]

Great. Can you see what name it got?
i.e.

Mar 10 18:23:53 dnsmasq-dhcp[1575]: DHCPDISCOVER(br0) 192.168.1.156 b0:05:94:25:d8:b3
Mar 10 18:23:53 dnsmasq-dhcp[1575]: DHCPOFFER(br0) 192.168.1.156 b0:05:94:25:d8:b3
Mar 10 18:23:53 dnsmasq-dhcp[1575]: DHCPREQUEST(br0) 192.168.1.156 b0:05:94:25:d8:b3
Mar 10 18:23:53 dnsmasq-dhcp[1575]: DHCPACK(br0) 192.168.1.156 b0:05:94:25:d8:b3 XXXXXXX

 

[den75]

Can't find what you're looking for in the log. The hostname is defined on the device itself.

 

[ColinTaylor]

Can't find what you're looking for in the log. The hostname is defined on the device itself.

Yes, but the device should register its name with the router as part of the DHCP process. In the example above the name is XXXXXXX.

So you see no name at all? That would explain the problem.

Also, can you now see the IP address in the router's Client List?

 

[den75]

Still can't see it in the client list, but I can access it with the IP

 

[ColinTaylor]

Hmm. That's a problem then. For some reason it's not registering its name with the router's DNS server. Which means DNS has no way of knowing the name of the device.

With Merlin's firmware you can manually assign a name to device. But with stock ASUS firmware (which I assume you're using) you can only do that by picking the device from the client list. If it isn't in the client list...

Let's try a different tack. What is the make and model number of the aquarium device?

Can you double check the network settings on the aquarium device and make sure that its name hasn't been accidentally cleared. Also, look to see if there's an option like "register name with DNS" and make sure it's enabled.

 

[den75]

I checked the name on the device, it's still "apex" DHCP is enabled. DNS server is 192.168.1.1 This is the device

https://www.neptunesystems.com/products/apex-controllers/apex-controller-system/

 

[den75]

Noticed there is no DNS server here on the router. Should there be?

 

[den75]

Also no default gateway

 

[ColinTaylor]

Noticed there is no DNS server here on the router. Should there be?

No. That's correct. Those fields should be empty.

I'm presuming that you don't have any entries under Manual Assignment?

 

[den75]

No, I don't. It's not even enabled