Manual DHCP Hostnames Aren't Always Being Used

[HarryMuscle]

I noticed that not all of the hostnames specified in my manual DHCP list can be resolved by other devices. I think the devices that can't be resolved are maybe supplying a different hostname during the DHCP request and that is being used instead. So I'm wondering about two things. Can I see the actual hostnames that DNSMasq is serving for all of the local devices. And is it possible to tell DNSMasq to use the hostnames specified in the manual DHCP list instead of (or maybe in addition to) any hostnames that the device might supply during the DHCP request?

Thanks,
Harry

 

[ColinTaylor]

Start by looking at System Log - DHCP leases.

 

[Morris]

Are the hosts set for DHCP?

 

[bbunge]

I noticed that not all of the hostnames specified in my static DHCP list can be resolved by other devices. I think the devices that can't be resolved are maybe supplying a different hostname during the DHCP request and that is being used instead. So I'm wondering about two things. Can I see the actual hostnames that DNSMasq is serving for all of the local devices. And is it possible to tell DNSMasq to use the hostnames specified in the static DHCP list instead of (or maybe in addition to) any hostnames that the device might supply during the DHCP request?

Thanks,
Harry

It is not a "static" DHCP list.

It is a Manually Assigned IP around the DHCP list.

Static IP addresses are assigned at the client.

 

[HarryMuscle]

It is not a "static" DHCP list.

It is a Manually Assigned IP around the DHCP list.

Static IP addresses are assigned at the client.

Fair enough. I've updated the terminology.

 

[HarryMuscle]

Are the hosts set for DHCP?

You mean the hostnames? Yes, I've filled in the hostnames for all of the manually assigned IP addresses.

 

[sfx2000]

I noticed that not all of the hostnames specified in my manual DHCP list can be resolved by other devices.

Why are you doing this?

If you have proper wireless security measures in place, and physical control over the wire...

 

[glens]

If "jack" is on 192.168.50.67 and running "host jack" returns nothing, what does the reverse lookup, "host 192.168.50.67" return? I guess if you don't have "host" and/or you just like typing more characters, use "nslookup" instead.

Also, what does "cat /etc/hosts" return?

 

[HarryMuscle]

Why are you doing this?

If you have proper wireless security measures in place, and physical control over the wire...

It's best to refer to devices by their hostname not their IP address but when I started doing that I noticed that some hostnames can't be resolved.

 

[HarryMuscle]

If "jack" is on 192.168.50.67 and running "host jack" returns nothing, what does the reverse lookup, "host 192.168.50.67" return? I guess if you don't have "host" and/or you just like typing more characters, use "nslookup" instead.

Also, what does "cat /etc/hosts" return?

I'll let you know as soon I can get back to this, likely Friday.

 

[bennor]

I noticed that not all of the hostnames specified in my manual DHCP list can be resolved by other devices. I think the devices that can't be resolved are maybe supplying a different hostname during the DHCP request and that is being used instead. So I'm wondering about two things. Can I see the actual hostnames that DNSMasq is serving for all of the local devices. And is it possible to tell DNSMasq to use the hostnames specified in the manual DHCP list instead of (or maybe in addition to) any hostnames that the device might supply during the DHCP request?

It may help if you post the router model, router firmware version, and network layout (AiMesh, Wifi Extenders, Power Line Extenders, etc.). If using Asus-Merlin are you running any add-on scripts?

Are the devices which are not returning the correct hostname on WiFI or Guest WiFi or a specific wired network segment (like a switch or hub)? If they are returning the wrong name, what name are they returning?

If you run cat /var/lib/misc/dnsmasq.leases using SSH does it return the correct hostnames?

 

[ColinTaylor]

Start by looking at System Log - DHCP leases.

 

[Morris]

You mean the hostnames? Yes, I've filled in the hostnames for all of the manually assigned IP addresses.

No, are the host's stacks configured to use DHCP to get an IP address?

 

[HarryMuscle]

Thanks for everyone's responses. I figured out the issue, a combination of Windows and router quirks.

I don't have a domain name set on the router which means it's technically a zero length string but Windows doesn't append this zero length string domain name when it tries to do local DNS resolution that are not fully qualified and for some reason the router doesn't resolve not fully qualified domain names. But as soon as you try to resolve the fully qualified domain name using a zero length string (ie: "printer." (notice the dot)) things work correctly. Also as soon as I add a domain name to the router Windows correctly appends it and everything works as excepted.

 

[Morris]

printer. is using NETBIOS name resolution. It works quite nicely for local hosts.