Date: Wed, 19 Jun 2019 16:35:46 -0700 (PDT) From: "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net> To: Eugene Grosbein <eugen@grosbein.net> Cc: "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net>, freebsd-net@freebsd.org, freebsd-questions@freebsd.org, "Ronald F. Guilmette" <rfg@tristatelogic.com> Subject: Re: Eliminating IPv6 (?) Message-ID: <201906192335.x5JNZkBd020541@gndrsh.dnsmgr.net> In-Reply-To: <1633b96e-15ba-9933-abea-46e7b4f0e6a2@grosbein.net>
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> 19.06.2019 22:42, Rodney W. Grimes wrote: > > >> 18.06.2019 10:10, Ronald F. Guilmette wrote: > >>> How can I turn off IPv6 entirely without rebuilding the kernel? > >> You cannot. GENERIC kernel specifically enables IPv6 support and you need to disable it at compile time. > >> And if you do, you better rebuild the world too using WITHOUT_INET6=yes in the /etc/src.conf > >> or else some utilities compiled with INET6 by default will query kernel > >> for IPv6-specific data (like routing entries) and complain that your kernel does not know about it. > > I have not seen these issues, can you give a specific example that fails? > > Other than kernel/userland interaction (that may be not relevant anymore for modern FreeBSD), > that's basically about making network connections (such as telnet etc.) > to FQDNs resolved to IPv6 addresses supported by binaries (and resolver being userland beast) > but not kernel/routing table. > > > A netstat -rn on a v4 only kernel simple reports the v4 table, and iirc a > > netstat -rn6 returns a "Protocol not supported error" as should all other > > things. > >> World built WITHOUT_INET6 has no such rough edges. > > I find that actually causes me more issues, as then my > > netstat -rn6 returns a hard error due to: > > case '6': > > #ifdef INET6 > > af = AF_INET6; > > #else > > errx(1, "IPv6 support is not compiled in"); > > #endif > > Seems very logical to me. Do we have a script in base running "netstat -rn6" > and breaking on this? Again, why does it need to be in base? Since when was that the standard by which we measure proper function? Basically the above #else is probably not the best of ideas... silently ignoring the -6 would of been a more gracefull solution possibly. -- Rod Grimes rgrimes@freebsd.org
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