Date: Wed, 24 Jul 2002 23:18:46 +0900 From: JINMEI Tatuya / =?ISO-2022-JP?B?GyRCP0BMQEMjOkgbKEI=?= <jinmei@isl.rdc.toshiba.co.jp> To: Don Lewis <dl-freebsd@catspoiler.org> Cc: net@FreeBSD.ORG Subject: Re: disabling IPv6 *without* recompiling the kernel Message-ID: <y7vr8htgqex.wl@ocean.jinmei.org> In-Reply-To: <200207210333.g6L3XAwr041931@gw.catspoiler.org> References: <200207210333.g6L3XAwr041931@gw.catspoiler.org>
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>>>>> On Sat, 20 Jul 2002 20:33:10 -0700 (PDT), >>>>> Don Lewis <dl-freebsd@catspoiler.org> said: > I've run into the same problems with Mozilla that many other people have > reported. (...snip) Thanks for the careful check and suggestions. I think we should take them seriously. But before that, please let me check something: > Even though I'm on an IPv4 only network, I'm seeing DNS > lookups for AAAA records, many of which are timing out due to problems Does the DNS servers have A records for the same name? If so, it should not take a long time out to resolve the corresponding AAAA records. The authoritative server should just return a response with the empty answer section. Or, are you talking about an unreachable server that even cannot return the A records, and the AAAA query doubles the total delay? Some DNS servers behave very badly; they responds to AAAA queries with the NXDOMAIN code, and, as a result, suppress further queries even when they have an A record. We should fix such servers, but, IMHO, we do not have to change the resolver side behavior just due to this. > I'm also seeing long pauses when > Mozilla attempts to connect to various web sites which I suspect are > caused by Mozilla's attempts to connect to unreachable IPv6 addresses. Regarding this issue, what do you mean by "an IPv4 only network"? More specifically, - do you have any non-link-local IPv6 addresses? - do you have an IPv6 default router? If the answer is "no" for both, then the connection attempts to the IPv6 destinations should immediately fail with EHOSTUNREACH and the delay should not matter in usual operation. So, basically even if you have some link-local IPv6 addresses and the IPv6 loopback address, neither of the AAAA queries nor the connection attempts to IPv6 destinations should matter. If you saw exceptions, I'd like to know more details. Thanks, JINMEI, Tatuya Communication Platform Lab. Corporate R&D Center, Toshiba Corp. jinmei@isl.rdc.toshiba.co.jp To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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