Gl-BE9300 : upstream DNS server resolver failures

[hanasaki]

Gl-BE9300 : upstream DNS server resolver failures

Running Admin Panel v4.8.3

The router gets a DHCP address and upstream DNS server from the WAN port

wifi clients resolve “host IP” fine (IP is in the DNS server provided by DHCP to the router)

wifi clients fail to resolve “host HOSTNAME” even when the hostname is copied directly from what was returned from host IP

==

NOTE: i was trying to ssh into the router to check resolve.conf however cannot figure out hot to connect. There is no terminal in the GUI, dropbear is installed, router is not listening on TCP 22.

I am not on guest wifi

[will.qiu]

Hi

Could you please confirm whether your upstream network is providing DHCP Options 15 and 119?
These options supply the required information for downstream routers to automatically append DNS suffixes.

As an alternative, you can manually add the required domain suffixes under LuCI → Network → DHCP and DNS → Local domain.

Additionally, SSH is enabled by default.
Please verify its status in GL UI → System → Security.

If you still encounter any issues, please try to provide a detailed network topology, including IP addresses and the corresponding search domain locations, so we can better assist you.

[hanasaki]

• OK - SSH issue resolved - It was set to the default of OFF.
• Linux clients of the upstream DHCP auto set their domain correctly however the 9300 does not seem to set it. I manually changed it from lan to the correct domain and the linux client has the correct domain. I had done this before contacting you. The issue still persists.
  • on Linux client of router: host 10.1.1.100 gives the hostname : host HOSTNAME fails. This works fine on a client directly connected via ethernet to the internal server.
• laptop (wifi) → 9300 (ethernet) → internal dhcp/dns (debian trixie) →inet

Thank you.

[will.qiu]

To make sure we’re troubleshooting the right setup, could you confirm which topology matches your current network?

1. BE9300 as a secondary router, with a Debian device providing DHCP/DNS on the primary router side.
   

   

2. BE9300 as the primary router (DHCP/DNS disabled), with a Debian device providing DHCP/DNS within the same subnet.
   

   

[hanasaki]

sorry those diagrams do not quite fit.

I will try to explain below.

Internet - router with dns/dhcp (A)

A - linux workstation (B1) via ethernet

A - BE9300 - wifi linux laptop (B2)

==

B1 works fine

B2 has the issues.

[will.qiu]

Thank you for clarifying the topology.

To confirm, the BE9300 is currently operating in router mode with DHCP and DNS enabled, and HOSTNAME queries are expected to be resolved by the primary router. Is that correct?

If so, please go to LuCI → Network → DHCP and DNS and check the following:

1. Make sure no relevant suffixes are configured under “Resolve these locally” or “Local domain”.
   

   

2. Open the Filter tab and disable:

• Domain required, so DNS queries without dots or domain parts are forwarded to the upstream DNS server.
• Filter private, so reverse DNS (PTR) requests are forwarded to the upstream DNS server.
  
  

3. Then restart the router and laptop for the settings to take effect.

---

Additionally, if the BE9300 does not require any routing-related functions, switching it to AP mode may be a quicker and more convenient solution.

Network Mode - GL.iNet Router Docs 4

[hanasaki]

so my wifi connected laptop has the correct resolve.conf of the below from the BE9300

==

search home.hanaden.com
nameserver 192.168.8.1

==

The laptop also looks up the host fine for

host HOSTNAME [IP-OF-INTERNAL-DNS-SERVER]

it also finds the reverse DNS ok.

It just seems the the wifi router is not forwarding requests that it cannot fulfill to the upstream DNS server.

[hanasaki]

BE9300 is configured correctly to use the upstream server.

[hanasaki]

I may have been connected differently that I thought.

Things seem stable and working now, so, shall we give it a few days confirm?….

There is one small, annoying, remaining issue that shows up as:

==

host firewall
firewall.home.hanaden.com has address 10.1.1.1
Host firewall.home.hanaden.com not found: 3(NXDOMAIN)
Host firewall.home.hanaden.com not found: 3(NXDOMAIN)

==

Note: the last two error lines in the about output. This is from the linux host connected to the BE9300 on non-guest wifi. Note that bypassing the BE9300 DNS completely has no error, so I believe the issue to be from the BErouter.

host firewall 10.1.1.1
Using domain server:
Name: 10.1.1.1
Address: 10.1.1.1#53
Aliases:

firewall.home.hanaden.com has address 10.1.1.1

Thank you

[will.qiu]

The two error lines in the output may be expected behavior and could be caused by the following:

1. Multiple DNS servers in /etc/resolv.conf
   When using the host command, queries are sent to all listed DNS servers, and all responses are shown. If only one server responds successfully, this is normal—the others may return NXDOMAIN.
   (Since manually specifying a DNS server works correctly, this is a likely explanation.)

2. Additional record types queried by host
   By default, host queries not only A records but also AAAA and MX records. If these records do not exist for the domain, NXDOMAIN may be shown.

   To test only A records, you can run:

   host -t A firewall
   

[hanasaki]

on the 9300 wifi client

on the 9300

SSH info from router

[hanasaki]

Might have resolved the issue. Still testing…

AdGuard Home Handle Client Requests was enabled = TRUE

solution set to FALSE

[will.qiu]

Yes. If you are using AdGuard Home, please do one of the following:

1. Disable “AdGuard Home Handle Client Requests”, allowing DNS queries to be forwarded to dnsmasq first.
2. Or explicitly define upstream DNS servers in AdGuard Home → Upstream DNS servers, such as:

[//]10.1.1.1
[/home.hanaden.com/]10.1.1.1

Refer: Configuration · AdguardTeam/AdGuardHome Wiki · GitHub