curl / Mailing Lists / curl-library / Single Mail

Buy commercial curl support from WolfSSL. We help you work out your issues, debug your libcurl applications, use the API, port to new platforms, add new features and more. With a team lead by the curl founder himself.

Re: Happy Eyeballs doesn't seem to work with c-ares when IPv6 name servers on top of the name server list don't respond

Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ] [ by messages with attachments ]

From: Cristian Rodríguez via curl-library <curl-library_at_lists.haxx.se>
Date: Thu, 25 Nov 2021 23:25:45 -0300

On Thu, Nov 25, 2021 at 11:10 PM Cristian Rodríguez
<crrodriguez_at_opensuse.org> wrote:
>
> On Wed, Nov 24, 2021 at 11:12 PM Dmitry Karpov via curl-library
> <curl-library_at_lists.haxx.se> wrote:
>
>
> > Is it possible to work around this issue somehow?
>
>
> Yes, keep a local dns cache running and query that instead, nowadays
> most newer distros ship with systemd-resolved.. if that's not what you
> want, unbound will do the trick.
>
> To make sure my thoughts on this are correct can you tell me what icmp
> error you get ON THE WIRE about :
>
> IPv6 server1 <not responding>
>
> IPv6 server2 <not responding>
>
> and does the attached c-ares patch make any difference?

To make it more clear..the linux kernel does not consider a fatal
error the following icmp errors on connected UDP sockets:

Destination Host unreachable,
destination Net unreachable
Source Route Failed
Fragmentation Required

So, the socket is doomed to reach whatever timeout c-ares have.. this is a subtl

-- 
Unsubscribe: https://lists.haxx.se/listinfo/curl-library
Etiquette:   https://curl.haxx.se/mail/etiquette.html

Received on 2021-11-26

Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ] [ by messages with attachments ]