DNS error for ch3.vpn.airdns.org

[spinmaster 30]

I have a config file for each region to select the best server from that part of the world (Earth, Europe, US, Germany, Switzerland, etc.) I noticed a few days ago that for the Swiss region, the DNS cannot be resolved any longer:

spinmaster@MacBook AirVPN % sudo ./hummingbird AirVPN_Switzerland_UDP-443-Entry3.ovpn
(…)
Mon Jul 18 18:59:59.052 2022 Network filter and lock successfully activated
Mon Jul 18 18:59:59.053 2022 ERROR: RESOLVE_ERROR
Mon Jul 18 18:59:59.053 2022 Transport Error: DNS resolve error on 'ch3.vpn.airdns.org' for UDP session: Host not found (authoritative)
Mon Jul 18 18:59:59.053 2022 Client terminated, restarting in 2000 ms...
(…)

Did something change in the DNS for the Switzerland servers? If yes, how can users keep track of that? I haven’t seen any related annoucements...

[bavequwa 2]

Hi,

The domain resolves for me (opennic DNS).


ipleak.net resolves it too:
https://ipleak.net/?q=ch3.vpn.airdns.org

If I would say, it's something with your DNS provider, system DNS cache or hummingbird. Hard to tell.

[spinmaster 30]

Thanks @batou8 for checking. I just tried different DNS servers (I was using a censor free DNS in my router and have now checked with my Provider DNS) - but same result. So I am ruling my local DNS provider out...

If it's DNS cache related: any way of clearing or resetting this? I am just using Hummingbird with all of the deault settings and flags - nothing special. It works for all other countries, so it's weird that it does not work exclusively for the Switzerland region.

[bavequwa 2]

I'm not an Mac expert. One article mentions this:
https://www.makeuseof.com/how-to-flush-dns-cache-mac/

You can also try:
nslookup ch3.vpn.airdns.org
...in terminal to see if it resolves to IP address.
 

[spinmaster 30]

Thanks for helping out! OK, tried some things, very interesting: It looks like I can resolve the host on my Mac by using the Provider DNS:

spinmaster@MacBook ~ % dig ch3.vpn.airdns.org

; <<>> DiG 9.10.6 <<>> ch3.vpn.airdns.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 19072
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;ch3.vpn.airdns.org.		IN	A

;; ANSWER SECTION:
ch3.vpn.airdns.org.	184	IN	A	79.142.69.162

;; Query time: 13 msec
;; SERVER: 172.30.11.1#53(172.30.11.1)
;; WHEN: Thu Jul 21 19:08:20 CEST 2022
;; MSG SIZE  rcvd: 63

I then tried clearing the DNS cache (as described on the website you mentioned):

spinmaster@MacBook ~ % sudo killall -HUP mDNSResponder

However, I still cannot connect via Hummingbird - getting the same error from my initial post. I assume it must be something with Hummingbird maybe, but I'm not sure how to further debug this...

Very weird!

P.S. Re-Created the Config-Files (tested with UDP and TCP) for Switzerland, but no luck either.