DNS server

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kosta88
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Joined: February 6th, 2021, 5:32 pm

DNS server

Post by kosta88 »

Hello,
can someone please explain me why is Sabnzbd forcing usage of Google DNS server to resolve usenet server? Shouldn't it use default system DNS?
Thank you
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sander
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Re: DNS server

Post by sander »

What makes you think SAB uses Google's DNS?
kosta88
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Joined: February 6th, 2021, 5:32 pm

Re: DNS server

Post by kosta88 »

tcpdump -i docker0 dst port 53
15:38:03.090188 IP 172.17.0.2.36465 > dns.google.domain: 49882+ [1au] AAAA? news-eu.newshosting.com. (52)
15:38:08.092279 IP 172.17.0.2.49125 > dns.google.domain: 41662+ [1au] A? news-eu.newshosting.com. (52)
15:38:13.096100 IP 172.17.0.2.53754 > dns.google.domain: 41662+ [1au] A? news-eu.newshosting.com. (52)
15:38:18.100091 IP 172.17.0.2.49125 > dns.google.domain: 41662+ [1au] A? news-eu.newshosting.com. (52)
15:38:23.105187 IP 172.17.0.2.53754 > dns.google.domain: 41662+ [1au] A? news-eu.newshosting.com. (52)

And the fact that my firewall (OPNsense) reports it too. And the fact they never come in on my Pi-hole.
Docker host is set to Pi-hole.
172.17.0.2 is the SABnzbd Docker.
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sander
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Re: DNS server

Post by sander »

Ah, within docker. If you go into docker (docker excec /bin/sh), and do a host / nslookup from the CLI, ... does it use Google DNS ... ?

If so, it's a docker OS thing.

The other way around: SAB is open source and scripted ... so if it would use a Google DNS, you should be able to find it in the source code ... Did you check that?
kosta88
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Joined: February 6th, 2021, 5:32 pm

Re: DNS server

Post by kosta88 »

Not so much a Linux guy... I an in the Docker shell, but there is no tcpdump, so not sure what further.
But, if that helps, no other containers do that.

Unfortunately, I have nothing to do with scripting or programming. I just wanted to point out, that's all, if at all someone wants to take a look at that.
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sander
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Re: DNS server

Post by sander »

Your question "can someone please explain me why is Sabnzbd forcing usage of Google DNS server to resolve usenet server?" contains a statement, so I assumed you checked it yourself before stating that.

Now it's a bit like "Have you stopped beating your wife?'. Quite hard to answer. Ah, wikipedia tells that's a Loaded Question. TIL.

Better:
Q: "Does SABnzbd force use Google DNS".
A: No

The underlying OS handles DNS requests. In case of Docker: the Docker DNS settings. You can check them yourself. Hint /etc/resolv.conf

Or ... can you ask the creator of your Docker image.
kosta88
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Joined: February 6th, 2021, 5:32 pm

Re: DNS server

Post by kosta88 »

Wasn't meant to be misunderstood. It was clear to me, but apparently shot in the wrong direction.
Thanks, will look into that.
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