From owner-freebsd-net@freebsd.org Sat Dec 21 08:33:50 2019 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id A20BC1CCA37 for ; Sat, 21 Dec 2019 08:33:50 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 47fzRL3stJz42b0 for ; Sat, 21 Dec 2019 08:33:50 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id 82D971CCA35; Sat, 21 Dec 2019 08:33:50 +0000 (UTC) Delivered-To: net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 816B61CCA34 for ; Sat, 21 Dec 2019 08:33:50 +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) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 47fzRL2NVbz42Zy for ; Sat, 21 Dec 2019 08:33:50 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4D227CC25 for ; Sat, 21 Dec 2019 08:33:50 +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 xBL8Xo98008437 for ; Sat, 21 Dec 2019 08:33:50 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id xBL8XodK008436 for net@FreeBSD.org; Sat, 21 Dec 2019 08:33:50 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 242744] IPSec in transport mode between FreeBSD hosts blackholes TCP traffic Date: Sat, 21 Dec 2019 08:33:50 +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: 12.1-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: vas@sibptus.ru X-Bugzilla-Status: Open X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: net@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: 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 MIME-Version: 1.0 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 Dec 2019 08:33:50 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D242744 --- Comment #5 from Victor Sudakov --- (In reply to Eugene Grosbein from comment #4) > First, one can use IPSec transport mode combined with gif tunnel and mtu= =3D1500 for the gif.=20 The solution with gif or if_ipsec tunnels is not scalable if you want to cr= eate a mesh of hosts with protected traffic between them. If we are talking about not more than 2-3 hosts, then the if_ipsec solution is the most elegant.=20 > Second, one can try sysctl net.inet.ipsec.dfbit=3D0 that is documented in= =20 > ipsec(4) manual page for IPSec tunnel mode=20 > but maybe it works for transport mode, too I wrote in the initial problem description that this sysctl does not work f= or transport mode. You just did not pay attention. > Third, you can adjust TCP MSS by means of packet filters.=20 I don't think I can if the packet in question is not received or transmitted via any interface (like locally generated ssh-client traffic intercepted by IPSec policies). Or I'll try if you provide an example of matching such a packet. I also tried pf's "scrub out proto 50 no-df" but there was no match. In a FreeBSD - Windows 7 combination, this kind of transport mode works transparently out of the box. I think Windows knows to adjust MSS, or something. --=20 You are receiving this mail because: You are the assignee for the bug.=