DNS_RRL_MAX_RATE defines 1000

[Zhiyong Cheng]

Thanks for this reply : )

We are using named cluster in our internal network as the authoritative DNS. So there are no cache servers between clients and named cluster. Maybe we should add one but it is just another story.

There was a strange thing when I tested RRL using queryperf.  I generated 10000 qnames to test.txt and every qname queried once. The queryperf’s output pastes below:

Statistics:

 Parse input file: once
 Ended due to: reaching end of file

 Queries sent: 10000 queries
 Queries completed: 9820 queries
 Queries lost: 180 queries
 Queries delayed(?): 0 queries

 RTT max: 0.009435 sec
 RTT min: 0.000072 sec
 RTT average: 0.000503 sec
 RTT std deviation: 0.000785 sec
 RTT out of range: 0 queries

 Percentage completed: 98.20%
 Percentage lost: 1.80%

 Started at: Thu Jul 9 11:16:03 2020
 Finished at: Thu Jul 9 11:16:48 2020
 Ran for: 45.300412 seconds

 Queries per second: 216.775070 qps

The named rate-limiting logs pastes below:

09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b44ed190 10.0.0.10#38722 (anvq.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4414020 10.0.0.10#38722 (anwi.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4518840 10.0.0.10#38722 (anvf.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4552680 10.0.0.10#38722 (anvx.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b44dea00 10.0.0.10#38722 (anwa.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4487ca0 10.0.0.10#38722 (anva.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4405890 10.0.0.10#38722 (anwg.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4526fd0 10.0.0.10#38722 (anvr.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b446ad80 10.0.0.10#38722 (anvs.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4430f40 10.0.0.10#38722 (anvh.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b44227b0 10.0.0.10#38722 (anvj.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b450a0b0 10.0.0.10#38722 (anvm.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b44a4bc0 10.0.0.10#38722 (anwe.internal): view xxxx: rate limit drop all response to 10.0.0.10/32
09-Jul-2020 11:16:54.055 rate-limit: info: client @0x7f83b4496430 10.0.0.10#38722 (anwh.internal): view xxxx: rate limit drop all response to 10.0.0.10/32

To my mind the RRL should not limit queries with different qnames from the same client. So is it my misunderstanding or wrong config?

BIND version pastes below:

version: BIND 9.11.4-P2 (Extended Support Version) <id:7107deb>
在 2020年7月8日 +0800 PM11:45，Tony Finch <dot at dotat.at>，写道：
> 程智勇 <chengzhycn at gmail.com> wrote:
> >
> > So could anybody tell me why DNS_RRL_MAX_RATE defined 1000?
>
> RRL is designed for authoritative DNS servers. Legitimate queries come
> from recursive resolvers with caches. There should not be more than one
> query for each RRset from each resolver per TTL. So a normal response rate
> limit is relatively small - I set it to 10.
>
> If you are hitting 1000 queries per second, that implies either there
> are 1000 resolvers behind one IP address (which is VERY unlikely); or the
> query traffic is abusive.
>
> Are you sure the dropped traffic is legitimate?
>
> Tony.
> --
> f.anthony.n.finch <dot at dotat.at> http://dotat.at/
> Channel Islands: West to southwest 4 to 5, occasionally 6 mid-channel
> overnight and Thursday morning, occasionally west to northwest 2 to 4 in the
> far south of the area. Slight to moderate with a low swell, perhaps
> occasionally rather rough mid-channel until late morning. Occasional mist and
> fog, especially overnight rain and drizzle at times, especially from Thursday
> morning. Moderate to poor or very poor, locally good at times.
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