DNS storm causes DDOS on my network every 60mn

[Pierrem31 (Pierre)]

Hello everyone,

For the past few weeks, I’ve been dealing with a rather “funny” issue with Home Assistant that has a significant impact on my network.

After every reboot—and then exactly every 60 minutes from that point—my HA instance sends thousands of DNS requests within a few seconds, which causes my entire local network to freeze.

I spent several weeks troubleshooting, starting from the initial symptom (network freeze) all the way to identifying Home Assistant as the root cause. I’m now confident that HA is responsible.

I’ve come across a few posts mentioning similar issues, but the suggested solutions aren’t very clear to me.

This behavior started after one of these changes:

• A Home Assistant Core update
• A Zigbee2MQTT update
• A firmware update on my ASUS router

What I’ve Tried So Far :

Changed HA’s IP (reserved in DHCP)
Disabled some HA add-ons (like Music Assistant, Telegram)
Switched DNS from Cloudflare to 8.8.8.8
Downgraded router firmware
Confirmed no Wake-on-LAN on the network
Checked DNS lease time (default: 86400s)

I’d really appreciate your advice on how to properly fix this.

Below, I’ve included a quick diagram of my current network setup, along with logs from both my Asus router and HA itself.

Thank you for your help!

DNS log on HA

> 2025-05-09 09:28:40.595 homeassistant dockerd[627]: time="2025-05-09T09:28:40.595092870Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:56837" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:56837->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t A"
> 2025-05-09 09:28:40.596 homeassistant dockerd[627]: time="2025-05-09T09:28:40.595253535Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:51776" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:51776->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t AAAA"
> 2025-05-09 09:28:43.096 homeassistant dockerd[627]: time="2025-05-09T09:28:43.096672006Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:50273" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:50273->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t AAAA"
> 2025-05-09 09:28:43.097 homeassistant dockerd[627]: time="2025-05-09T09:28:43.096698913Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:50248" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:50248->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t A"
> 2025-05-09 09:28:45.604 homeassistant dockerd[627]: time="2025-05-09T09:28:45.604049062Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:36780" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:36780->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t A"
> 2025-05-09 09:28:45.604 homeassistant dockerd[627]: time="2025-05-09T09:28:45.604060080Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:57390" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:57390->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t AAAA"
> 2025-05-09 09:28:48.105 homeassistant dockerd[627]: time="2025-05-09T09:28:48.105544626Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:39129" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:39129->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t AAAA"
> 2025-05-09 09:28:48.107 homeassistant dockerd[627]: time="2025-05-09T09:28:48.105629625Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:51336" dns-server="udp:9.9.9.9:53" error="read udp 192.168.1.100:51336->9.9.9.9:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t A"
> 2025-05-09 09:28:52.106 homeassistant dockerd[627]: time="2025-05-09T09:28:52.106648686Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:38600" dns-server="udp:192.168.1.1:53" error="read udp 192.168.1.100:38600->192.168.1.1:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t AAAA"
> 2025-05-09 09:28:52.107 homeassistant dockerd[627]: time="2025-05-09T09:28:52.107249531Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:192.168.1.100:37319" dns-server="udp:192.168.1.1:53" error="read udp 192.168.1.100:37319->192.168.1.1:53: i/o timeout" question=";o427061.ingest.sentry.io.\tIN\t A"

Log on asus

16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=33277 DF PROTO=TCP SPT=40956 DPT=853 SEQ=356465925 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=12747 DF PROTO=TCP SPT=39974 DPT=853 SEQ=4250102778 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=46327 DF PROTO=TCP SPT=40958 DPT=853 SEQ=2106520644 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=10109 DF PROTO=TCP SPT=40004 DPT=853 SEQ=1953116849 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=21397 DF PROTO=TCP SPT=39992 DPT=853 SEQ=1386308144 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=18371 DF PROTO=TCP SPT=40030 DPT=853 SEQ=2173235087 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.1.1.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=16400 DF PROTO=TCP SPT=59840 DPT=853 SEQ=2284892309 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080AB0CB3E990000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=10143 DF PROTO=TCP SPT=39990 DPT=853 SEQ=857774310 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=21735 DF PROTO=TCP SPT=40014 DPT=853 SEQ=4022992539 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478450000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.1.1.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=47958 DF PROTO=TCP SPT=60006 DPT=853 SEQ=2893571359 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080AB0CB3E990000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.1.1.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=45306 DF PROTO=TCP SPT=60606 DPT=853 SEQ=3456848711 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080AB0CB3EB90000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=40519 DF PROTO=TCP SPT=40196 DPT=853 SEQ=4181429377 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478650000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.1.1.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=59885 DF PROTO=TCP SPT=59864 DPT=853 SEQ=642377711 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080AB0CB3EB90000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=14598 DF PROTO=TCP SPT=40046 DPT=853 SEQ=1993664808 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478650000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=9.9.9.9 LEN=82 TOS=0x00 PREC=0x00 TTL=62 ID=44676 DF PROTO=UDP SPT=48396 DPT=53 LEN=62 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.0.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=45251 DF PROTO=TCP SPT=41006 DPT=853 SEQ=3076760472 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080A019478C50000000001030307) 
16/05/2025 18:54	GT-AC5300-A9C0-8393BAC-C	kernel:	ACCEPT IN=br0 OUT=eth0 MAC=0c:9d:92:aa:a9:c0:dc:a6:32:c4:57:04:08:00 SRC=192.168.1.80 DST=1.1.1.1 LEN=60 TOS=0x00 PREC=0x00 TTL=62 ID=30685 DF PROTO=TCP SPT=60036 DPT=853 SEQ=2495947027 ACK=0 WINDOW=64240 RES=0x00 SYN URGP=0 OPT (020405B40402080AB0CB3F790000000001030307) 

System Information

version	core-2025.5.1
installation_type	Home Assistant OS
dev	false
hassio	true
docker	true
user	root
virtualenv	false
python_version	3.13.3
os_name	Linux
os_version	6.6.74-haos-raspi
arch	aarch64
timezone	Europe/Paris
config_dir	/config

Home Assistant Community Store

GitHub API	ok
GitHub Content	ok
GitHub Web	ok
HACS Data	ok
GitHub API Calls Remaining	5000
Installed Version	2.0.5
Stage	running
Available Repositories	1770
Downloaded Repositories	5

Home Assistant Cloud

logged_in	false
can_reach_cert_server	ok
can_reach_cloud_auth	ok
can_reach_cloud	ok

Home Assistant Supervisor

host_os	Home Assistant OS 15.2
update_channel	stable
supervisor_version	supervisor-2025.05.1
agent_version	1.7.2
docker_version	28.0.4
disk_total	56.4 GB
disk_used	8.6 GB
healthy	true
supported	true
host_connectivity	true
supervisor_connectivity	true
ntp_synchronized	true
virtualization
board	rpi4-64
supervisor_api	ok
version_api	ok
installed_addons	Node-RED (19.0.2), Mosquitto broker (6.5.1), Zigbee2MQTT (2.3.0-1), File editor (5.8.0), Terminal & SSH (9.17.0), Log Viewer (0.17.1)

Dashboards

dashboards	3
resources	4
views	6
mode	storage

Network Configuration

adapters	lo (disabled), end0 (enabled, default, auto), docker0 (disabled), hassio (disabled), vethd8b4d24 (disabled), veth9566c28 (disabled), vethde5b40d (disabled), veth2b4f503 (disabled), veth8671af4 (disabled), veth0692c0e (disabled), veth4182c2f (disabled), veth1d75b21 (disabled), vethe2d315e (disabled), vethdd74bbb (disabled), vethcd88876 (disabled)
ipv4_addresses	lo (127.0.0.1/8), end0 (192.168.1.80/24), docker0 (172.30.232.1/23), hassio (172.30.32.1/23), vethd8b4d24 (), veth9566c28 (), vethde5b40d (), veth2b4f503 (), veth8671af4 (), veth0692c0e (), veth4182c2f (), veth1d75b21 (), vethe2d315e (), vethdd74bbb (), vethcd88876 ()
ipv6_addresses	lo (::1/128), end0 (fe80::94f3:7dab:bcb8:8053/64), docker0 (fe80::d88d:9bff:fef9:987/64), hassio (fe80::80bf:77ff:fe3e:eaed/64), vethd8b4d24 (fe80::5c4b:59ff:fe60:874/64), veth9566c28 (fe80::8872:ddff:fea7:6cab/64), vethde5b40d (fe80::4c00:1dff:fe66:2686/64), veth2b4f503 (fe80::c8c:9eff:fe88:aed2/64), veth8671af4 (fe80::8c78:afff:fe42:2b9b/64), veth0692c0e (fe80::7ce2:d4ff:fe80:b202/64), veth4182c2f (fe80::6c1b:34ff:fe04:fd7a/64), veth1d75b21 (fe80::3407:fdff:fed0:6ae9/64), vethe2d315e (fe80::1cfb:4cff:fea5:6d06/64), vethdd74bbb (fe80::9860:1fff:fea3:71f/64), vethcd88876 (fe80::b036:38ff:fe50:1286/64)
announce_addresses	192.168.1.80, fe80::94f3:7dab:bcb8:8053

Recorder

oldest_recorder_run	May 6, 2025 at 12:47
current_recorder_run	May 16, 2025 at 17:53
estimated_db_size	67.66 MiB
database_engine	sqlite
database_version	3.48.0

[Sir_Goodenough ((SG) WhatAreWeFixing.Today)]

@Pierrem31

Disabled some HA add-ons (like Music Assistant, Telegram)

Did you disable all Add-ons and Custom Integrations in groups. It’s very likely one of them.

2024.5+: Tracking down instability issues caused by integrations

If your system is unstable due to a misbehaving integration, there are several ways to identify and recover from the issue. It’s recommended to enable Home Assistant’s debug mode and asyncio debug mode to collect detailed logs and diagnose the root cause. Using Home Assistant's Built-In Debug Mode (2024.5.x or later – Recommended) Enabling Asyncio Debug Mode at Runtime (Preferred with Debug Mode) Enabling Asyncio Debug Before Startup (Fallback Plan) 🛠️ Manually Enabling Safe Mod…

[WallyR (Wally)]

9.9.9.9 is Quad9’s DNS server and that is the one that stops responding, but I do not think have use it normally.
The DNS service from Quad9 is aiming to block malware domains, so maybe a malware scanner somewhere in your setup.

[Pierrem31 (Pierre)]

So I think I’ve got the beginnings of an answer, at least my network no longer freezes:
There was probably a block on my router’s side, which forbade DNS resolution for certain outgoing IPs.
These blocks would prevent TimeOut of 30 seconds, times hundreds (thousands?) of requests.
I lifted these blocks, no more freeze!

I’m not really satisfied with what I’ve done on the router side, but it works! I’ll dig deeper later

Having said that, I still have 2 outgoing ip’s requesting reverse DNS for all 255 local ip’s, the resolution is done in hundredths of a second, but I still find it weird!

[INFO] 172.30.32.1:36616 - 13015 “PTR IN 252.1.168.192.in-addr.arpa. udp 55 false 1232” NXDOMAIN qr,rd,ra 44 0.057674322s
[INFO] 127.0.0.1:56417 - 19366 “PTR IN 245.1.168.192.in-addr.arpa. udp 55 false 1232” NXDOMAIN qr,rd,ra 44 0.015054163s

We’ll say problem solved until the next one!

Thank you all for your help on this topic

[Tamsy]

@Pierrem31

dealing with a rather “funny” issue with Home Assistant that has a significant impact on my network.

Seems to be the very same like THIS. Sadly dosen’t really fit into “… puts local control and privacy first.”

[ThisWayToo]

More background here:

https://community.home-assistant.io/t/ha-spamming-ptr-dns-lookups/143687/85

[Tamsy]

@ThisWayToo

More background here

Nice. Thank you for the pointer. I just disabled dhcp from default_config as suggested. Lets see whether the hourly DNS bursts stop.