How do you enable in the Asuswrt firmware so that local devices can run host/nslookup on a local IP and get its hostname that the router has recorded?

[torch]

Question answered - I see "domain-needed" in /etc/dnsmasq.conf

 

[ColinTaylor]

...but would a null domain be considered as a local domain?

Asus routers would treat it as such because of the the way it generates the config file. But the real problem is the clients (which is what you're actually using). For example the nslookup command in Windows behaves completely different than Ubuntu's. ping and dig also behave differently than nslookup. And there are differences again when using null domains. The list goes on and on... that's why I said "it only leads to confusion".

 

[drinkingbird]

On my AX88U I found that nslookup reports "non-existent" for static v4 ips when there is no manual assignment list and it is disabled. Adding or defaulting a DNS server address has no effect, in either case nslookup reports the right DNS. Once I enabled manual assignment and defined my static devices they showed up with the host name defined in the list.

There is no way for the router to know about static hostnames that aren't asking for DHCP leases. You'd need to manually add A and PTR records for those. One of the reasons that DHCP reservations are better than just assigning statics.

Some devices do not report their hostname when receiving a lease. If you look in the DHCP lease table you'll see * for them usually, or sometimes a name totally different from what you'd expect. Setting the name manually in the client list won't get them into DNS, a manual reservation is the only way. That will create both an A record and a PTR for it.

From my experience, what is shown in the DHCP table is the only DNS record, and if it says * there is no DNS at all. Regardless of what shows in the client list. It gets really confusing, for example, my Blu-Ray Player

DHCP shows *
Client list default is "HonHai" (the manufacturer of the NIC)
I changed client list to "BluRay"

NSlookup, ping, etc will not work to HonHai or BluRay, nor will a lookup of the IP return anything. If I create a static lease for it, both forward and reverse will work to whatever hostname I give it, and that hostname will now show up in the DHCP leases instead of *

Another example, my TV DOES report its hostname, as COM-MID1. I can look up that and its IP no problem. I customized it in the client list to "PanasonicTV". That cannot be looked up (reverse lookup of the IP still returns COM-MID1). If I give it a static lease with PanasonicTV, now I can ping that name and reverse will return that name, and DHCP leases now shows my customized name instead of the one the client reports.

As far as the domain goes, I've found if you leave it blank, it will pass through whatever your ISP assigns (though that was a long time ago, maybe the behavior has changed). In my case I have my own domain name but I don't want to interfere with internet lookups for that domain, so I just use "intra.mydomain.net". But home is a common one and makes sense too.

 

[drinkingbird]

I tried this. I do get the name my router has in its device table for most devices such as my roku, my phone, etc... But other devices like my Canon printer do not return the name from the device list. So i think it may somewhat device specific also.

Correct, if the device does not report back a hostname, the router will have no DNS for it.

 

[drinkingbird]

Have you tried setting a Domain Name on your LAN? It appears you have it blank or have it set to "in-addr.arpa"

FYI in-addr.arpa is the default domain for reverse DNS lookups. You'll always see that on PTR records (the record created for an IP address instead of a hostname, called the reverse lookup zone).

In-addr stands for "inverse address" (you'll notice the record has the IP backwards) and arpa = Address and Routing Parameter Area. .arpa is a reserved domain for a specific purpose, just like .local and some others.