Local DNS domain lookup is extremely slow

kfoley

1/12/23, 12:32 PM

I have a DNS server I use to route traffic to local services. For example, it points router.home.lan to my router.

However, when I try to visit this address in my browser on my Ubuntu machine, it takes an extremely long time to load. If I visit the page on my Macbook or use the IP address on my Ubuntu machine then the page to load instantly.

I believe it has something to do with the DNS resolution on my Ubuntu machine. Here is the output from host:

time host -v router.home.lan                                            
Trying "router.home.lan"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59318
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;router.home.lan.       IN  A

;; ANSWER SECTION:
router.home.lan.    2   IN  A   192.168.1.1

Received 49 bytes from 127.0.0.53#53 in 12 ms
Trying "router.home.lan"
;; connection timed out; no servers could be reached

Trying "router.home.lan"
;; connection timed out; no servers could be reached

host -v router.home.lan  0.01s user 0.01s system 0% cpu 20.021 total

The first result comes back instantly, then the next two time out after 10 seconds each. I get the same behavior with ping.

This only happens with my local services on the home.lan domain.

Changing nameserver in /etc/resolv.conf to the IP of my local DNS server fixes the problem, however that's not sustainable as it frequently gets overwritten and causes issues outside of my network.

0 + 0

dns

matigo

1/12/23, 3:34 PM

Would setting the IP address of the DNS server in `/etc/hosts` not give you the consistency you’re looking for?

kfoley

1/12/23, 4:36 PM

@matigo - the file says "This file is managed by man:systemd-resolved(8). Do not edit." and thus the changes I make are often overwritten. I've read that I can set the name server in the `/etc/resolvconf/resolv.conf.d/base` file but that has no effect. Also, this DNS server only applies within my home which is why I'd rather not hard code it for the whole system.

Score:0

Ubuntu

heynnema

1/12/23, 3:36 PM

In terminal, type:

nm-connection-editor

And edit your "Wired Connection".

0 + 0

kfoley

1/12/23, 4:34 PM

I've tried setting both the "DNS Servers" as well as "additional search domains" to the relevant values but it doesn't seem to have an effect. However I did this for my wireless network instead of "Wired Connection" as my laptop doesn't have a wired connection.

heynnema

1/12/23, 4:44 PM

@kfoley Show me `cat /etc/resolv.conf`, then reboot, then show me `cat /etc/resolv.conf` again. Also show me `ls -al /etc/resolv.conf`.

heynnema

1/19/23, 1:21 PM

@kfoley Status please...

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Local DNS domain lookup is extremely slow

TH: การค้นหาโดเมน DNS ในเครื่องนั้นช้ามาก

RO: Căutarea domeniului DNS local este extrem de lentă

RU: Поиск локального домена DNS очень медленный

VI: Tra cứu tên miền DNS cục bộ cực kỳ chậm

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