Excessive DNS lookups for localhost

freundTech commented 2 years ago

The problem

I run my home-assistant on the same network as a pi-hole. A few months ago I noticed a ton of DNS requests to localhost and localhost.fritz.box (.fritz.box is the local domain set by my router and can't be changed. With another router it would probably be .local).

Pi-hole records between 430 and 450 dns requests to those two names per 10 minutes, which is 0.75 request per second. That is more DNS lookups than all other devices on my network combined, which is why I think that this is a bug.

I narrowed the source of the DNS requests down to home-assistant. I tried to narrow down which integration is responsible for the requests, but they still happen with all but the default integrations disabled. To make extra sure I even removed my configuration directory and restarted home-assistant to get a clean configuration and still got the DNS requests.

What version of Home Assistant Core has the issue?

core-2021.12.8

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant Container

Integration causing the issue

No response

Link to integration documentation on our website

No response

Example YAML snippet

No response

Anything in the logs that might be useful for us?

No response

Additional information

No response

frenck commented 2 years ago

.fritz.box is the local domain set by my router and can't be changed.

Definitely report that as an issue, as .box is a generic TLD owned by central nic and should never be used for internal networks.

jwshields commented 2 years ago

I am seeing a similar issue on my network.

PiHole is reporting that my Home Assistant VM is issuing hundreds of DNS requests for version.home-assistant.io

Home Assistant 2021.12.8
core-2021.12.8
Home Assistant OS 7.1
supervisor-2021.12.2

frenck commented 2 years ago

@jwshields care to share why that is an issue?

PS: absolutely not the same issue as this one imho, could you explain why it is the same issue?

jwshields commented 2 years ago

I am not saying it's the same issue, but a very similar one.
This seems to be new behavior (within the last month or so)

From the OP of this issue, @freundTech

Pi-hole records between 430 and 450 dns requests to those two names per 10 minutes, which is 0.75 request per second. That is more DNS lookups than all other devices on my network combined, which is why I think that this is a bug.

This is what I am keying off of, I am seeing hundreds of requests from my hassio VM. Nothing in the logs shows why this is happening. They're seemingly useless lookups.

frenck commented 2 years ago

I am not saying it's the same issue, but a very similar one.

Please don't stack different issues.

Nothing in the logs shows why this is happening. They're seemingly useless lookups.

I don't see the issue with that.

jwshields commented 2 years ago

I am not stacking different issues. The core that OP posted about is the numerous amount of lookups that were happening on their network. OP posted about lookups for localhost, I posted about lookups for version.home-assistant.io The issue is that there are large amounts of DNS requests happening for something happening behind the scenes that does not seem to be visible to end users. This is absolutely a concerning behavior; even when I turned on debug logging globally for hassio, nothing appeared in the logs for what was issuing those requests. That makes me so much more concerned than I already was.

I don't see the issue with that.

You are suggesting that 34 identical requests to resolve a hostname within the span of 1 second is acceptable/normal? I can't say I've ever used software that makes that many lookups, for the same thing, with a flood of requests, every five minutes. That's absurd.

frenck commented 2 years ago

I am not stacking different issues. The core that OP posted about is the numerous amount of lookups that were happening on their network.

You are misunderstanding the issue and stacking different issues actually.

localhost is internal and should not have been looked up / queried in the first place. However, you are reporting an external host lookup, which of course should take place externally.

Those are not the same things.

. This is absolutely a concerning behavior; You are suggesting that 34 identical requests to resolve a hostname within the span of 1 second is acceptable/normal?

You fail to answer or point out the issue that it is causing.

jwshields commented 2 years ago

The issue is that there is something in this system that is happening, which is not exposed to me/the OP/end users, the reasoning, the purpose, the source of it.

I do not want excessive DNS requests taking up CPU time on my DNS server and adding extra congestion to my networks. I would hazard most people would not want that as well. Is it difficult to understand that reasoning? Do we need to go deeper into the details and explain why I don't want CPU time consumed by useless spam? It's wasting cycles. For. No. Apparent. Benefit. Nor. Anything. That. I. Have. Control. Of.

You fail to answer or point out the issue that it is causing.

The problem is that there is SHIT HAPPENING ON MY NETWORK THAT I DO NOT CONDONE. THE ISSUE IS THAT I CANNOT TURN IT OFF OR IDENTIFY IT. Do I need to run around in any more circles to attempt to explain why this is problematic?

frenck commented 2 years ago

@jwshields Marking your comments for abuse and off-topic.

It is a different issue, additionally, the tone of your last comment is not acceptable and violates our CoC. Please consider this a warning.

jwshields commented 2 years ago

Acknowledged. I will not waste your time any more. My most sincere apologies for engaging with your open source project.

chemelli74 commented 2 years ago

I run my home-assistant on the same network as a pi-hole. A few months ago I noticed a ton of DNS requests to localhost and localhost.fritz.box (.fritz.box is the local domain set by my router and can't be changed. With another router it would probably be .local).

I'm a FritzBox user, so my attention was captured by this issue.

Stated that I cannot reproduce the issue, there are a couple of things that I would like to share:

localhost is a special host name that should resolved locally, not been sent to the DNS. If that happen means that local network layer is badly configured. For example hosts file is empty.
if an application sends a request for localhost.fritz.box then that is threated as standard request, so the hostname must exist in the DNS to get resolved. But if this happens sounds like a bug of the application that appends the domain when it shouldn't.

Simone

JensJott commented 2 years ago

I noticed this:

grafik

on my PiHole and found this thread. It's no big deal but seems odd for me.

I think this started when the GUI version sensors were introduced. I'm also using a FritzBox but my PiHole is running on another machine.

@freundTech can you confirm you also added that sensor? If so, try to disable it as a test.

github-actions[bot] commented 2 years ago

There hasn't been any activity on this issue recently. Due to the high number of incoming GitHub notifications, we have to clean some of the old issues, as many of them have already been resolved with the latest updates. Please make sure to update to the latest Home Assistant version and check if that solves the issue. Let us know if that works for you by adding a comment 👍 This issue has now been marked as stale and will be closed if no further activity occurs. Thank you for your contributions.

home-assistant / core