Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "Carlos E. R." Newsgroups: comp.os.linux.misc Subject: Re: Anybody Using IPv6? Date: Wed, 21 May 2025 19:16:08 +0200 Lines: 37 Message-ID: References: <100hijb$25ta5$5@dont-email.me> <100hl34$3of0i$1@news1.tnib.de> <100i89e$19k3$1@news1.tnib.de> <100i92h$2a8rb$3@dont-email.me> <100ieve$1o3d$1@news1.tnib.de> <100irbu$2j9c$1@news1.tnib.de> <100jqfp$4o04$1@news1.tnib.de> <100k1v0$2o6n2$1@dont-email.me> <100kcnb$649q$1@news1.tnib.de> <100kpc3$6vge$1@news1.tnib.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: individual.net LWbSBKHR0aD/ad7Ylgv6GAX7/G7hm/02VBA3B23+5bCwxNJjFb Cancel-Lock: sha1:UY2kZveuPTDqvJZ9AfLr2is0Jt8= sha256:4wVJPGehb46bbj9uYwq9wYBO3Ab/dMVx1iNvZQgw9W0= User-Agent: Mozilla Thunderbird Content-Language: en-CA, es-ANY In-Reply-To: <100kpc3$6vge$1@news1.tnib.de> Xref: csiph.com comp.os.linux.misc:67643 On 2025-05-21 16:52, Marc Haber wrote: > "Carlos E. R." wrote: >> On 2025-05-21 13:16, Marc Haber wrote: >>> I think that the local resolver should² also refrain from asking for >>> AAAA records if the local system doesn't have IPv6, but I don't know >>> whether this special-case handling is implemented at all. And I'm too >>> lazy to look that up. >>> >>> But all this needs to be taken into account before someone can comment >>> about speed of one IP protocol compared to the other on a level that >>> is beyond passing myths. >> >> It just is a perceived fact. On some machines, if an application gets >> back from the system a list of addresses to try, and tries IPv6 first >> when there is no actual IPv6 internet connectivity, there is a small >> delay waiting for the request to fail, and then try the next address in >> the list. > > pcap/strace or it didn't happen. Asking for a trace _now_ is ridiculous. It certainly did happen, and to to several people. Years ago. > > Please note that _broken_ IPv6, for example when the router announces > an IPv6 but the network doesn't return a host unreachable ICMPv6 > message from the place where connectivity is missing, will cause an > IPv6-enabled application to wait for the time out. But that is an > error in the _network_ setup, and should not happen in the case where > the end system (the one with the application running) has v6 enabled > on a non-v6-enabled network. > -- Cheers, Carlos E.R.