From nobody Fri Aug 06 10:34:41 2021 X-Original-To: net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 0703911FBD1A for ; Fri, 6 Aug 2021 10:34:42 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Gh20d6l4Rz3wHx for ; Fri, 6 Aug 2021 10:34:41 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id CE466450C for ; Fri, 6 Aug 2021 10:34:41 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 176AYfdV017883 for ; Fri, 6 Aug 2021 10:34:41 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 176AYf2p017882 for net@FreeBSD.org; Fri, 6 Aug 2021 10:34:41 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 218508] Tunneling and aliases using the tun device, reusing a destination address works with IPv4, but not IPv6 Date: Fri, 06 Aug 2021 10:34:41 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 11.0-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: zlei.huang@gmail.com X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: net@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cc Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D218508 Zhenlei Huang changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |zlei.huang@gmail.com --- Comment #3 from Zhenlei Huang --- (In reply to Christian Sturm from comment #0) The IPv6 stack does not behave the same as IPv4 stack. In this case, you can add an IPv6 alias without the destination address to tun0. ``` ifconfig tun0 inet6 2001:db8:: 2001:db8::1 prefixlen 128 ifconfig tun0 inet6 alias 2001:db8::2 prefixlen 128 ``` The long answer: In principle, a tunnel interface can be unnumbered. For a router, you can "borrow" the global unique address on loopback interface as the local addre= ss. As for numbered tunnel interface, is the peer should be numbered? No, at le= ast in principle not required. We give another thought on the remote address of tunnel interface, if both = ends are numbered, then should either end has only exactly one IP address? No. Due to historical reason, the destination address of tunnel interface can n= ot be omitted of the FreeBSD IPv4 stack implementation. But it is not the case= of IPv6 stack. Still we can teach the FreeBSD kernel to "smartly" process IPv6 aliases with same destination address. --=20 You are receiving this mail because: You are the assignee for the bug.=