[dnsdist] dnsdist 1.7 : allow only A request

david.neau at orange.com david.neau at orange.com
Mon Mar 20 07:43:52 UTC 2023

Hello Remi,

Thanks for your explanation about ANY and TCP, it makes sense

I shared my config in a previous mail in this thread.

Even if I m satisfied with my set up, having the same behavior about udp or TC requests would be a nice to have.
I have, of course, no idea about how to


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-----Message d'origine-----
De : dnsdist <dnsdist-bounces at mailman.powerdns.com> De la part de Remi Gacogne via dnsdist Envoyé : vendredi 17 mars 2023 17:04 À : dnsdist at mailman.powerdns.com Objet : Re: [dnsdist] dnsdist 1.7 : allow only A request


On 17/03/2023 16:23, david n via dnsdist wrote:
> BUT : for the "any" request I have this result, and I don't know if it can produce something bad, have you any idea ?
> [root at node ~]# dig any
> https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.t
> oto.com%2F&data=05%7C01%7Cdavid.neau%40orange.com%7C8233e8332c3d4ba167
> e408db270130b5%7C90c7a20af34b40bfbc48b9253b6f5d20%7C0%7C0%7C6381466582
> 84667428%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL
> CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=MAAj5Ab0X5jnqAesL8
> Vh7oSRbAS8m3B8ZXfGzJO4VoQ%3D&reserved=0 @X.X.X.X ;; communications 
> error to X.X.X.X#53: end of file ;; communications error to
> X.X.X.X#53: end of file

dig defaults to sending ANY queries over TCP, instead of UDP, and here dnsdist closes the TCP connection as soon as the query is dropped, triggering the message you are seeing. It's not clear to me why the connection is dropped from your configuration, though, have you shared the actual configuration?

dnsdist could keep the TCP connection around instead but it would be too nice, because timeouts over TCP are usually quite longer than over UDP and the connection would just sit there, consuming socket descriptors for nothing.

Hope that helps,

Best regards,
Remi Gacogne
PowerDNS.COM BV - https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.powerdns.com%2F&data=05%7C01%7Cdavid.neau%40orange.com%7C8233e8332c3d4ba167e408db270130b5%7C90c7a20af34b40bfbc48b9253b6f5d20%7C0%7C0%7C638146658284667428%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=wV4lEzjyBez%2BLvgvifeMbw5IjzoLltcD1AgbSJuiuaQ%3D&reserved=0


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