From nobody Mon Feb 5 13:30:21 2024 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 4TT6gy31KWz59x13 for ; Mon, 5 Feb 2024 13:30:22 +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 4TT6gy18NVz3wbx for ; Mon, 5 Feb 2024 13:30:22 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1707139822; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=f+PsHX9+7ZDZMHwBKhsETYfM1pMBA03R+025oWtunLE=; b=cYe4Oc1bLHkQhQuYMTpCiLdYUjzve+c0dFH49APXfNflPv879BQKREMwX5qa+txD8TD6Wn 9ihOFtjAdzmWODVWJC3SZNZD7qTn1eKeSmuMNvE9DJ/iUAOfY1UrBwYXvDLW/Tb26NtRfY TSn/dfyLTjDF83RV58/15GbFZy3dBzkMTm5RPmjlJs8A4RPf2s3ZVj9msYkkIco/UDpzjq hsioneNwZ13daApsleZJ+LgrKKhjgP7VoiLwB4/wU1xLFcrKj1ZoYEiW1MtnuqBSP4dLKo KdJ9OWUqM6sSTPnwlcLKjjFTijyZsQfqODxVZU2G5qYMCbuGgbl3FZPI15LuZA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1707139822; a=rsa-sha256; cv=none; b=mjP/35b9rHyeYvw7RzviVEeWAMXaD7ECotbsAWrZ8qq3fPftLu7zV85cPg4zUjYyvxXr7T Nt6owFcGby1RIg914XSS7Ea6f9/W1877KSZmRRZdcqaIABZOSbLF8BeajfDqqs5Mf0JdYu jWguuh5dnfFm8ciH2R6Um76M/XS9QAH8sV2NIRpnl67G16TsZ2txS3zC82FoZus+ckD+Zy +E53kIcVAYoWQLAOW6Dp9+peUrF1oyKWDYOmnF0MvCL4O6t7xDBw9eF9Ib0YH1EMDxDjqu 6vUg4Mmv1iC7t6uJFDXMsRnzE2oOX+SFCjASiQIL1XZ22AMKuX7TeTdWl03sBg== 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 4TT6gx74C3zhLB for ; Mon, 5 Feb 2024 13:30:21 +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 415DULif013263 for ; Mon, 5 Feb 2024 13:30:21 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 415DUL9P013262 for net@FreeBSD.org; Mon, 5 Feb 2024 13:30:21 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 276838] ovpn(4) DCO module breaks SSH connectivity Date: Mon, 05 Feb 2024 13:30:21 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 14.0-STABLE X-Bugzilla-Keywords: regression X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: gert@greenie.muc.de X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@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 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D276838 Gert Doering changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |gert@greenie.muc.de --- Comment #1 from Gert Doering --- As discussed on IRC, there are good chances that this is MTU related. If `mssfix` is in use, this will cap TCP packet size to "small enough so outside UDP packets do not need to be fragmented". This works both sides, = so it's enough if one end does `mssfix`. As of today, kernel openvpn does not seem to support `mssfix`, so if *both* ends use DCO, no MSS manipulations are done, and you need to reduce interfa= ce MTU (`tun-mtu 1400`) to get the same effect. Now, why outside fragmentation breaks with IPv6 is another of these questio= ns - it shouldn't break, it is tested here in my FreeBSD 14 / DCO test scenario,= but for example `pf(4)` needed to be told to leave IPv6 fragments alone in earl= ier versions (not sure about 14). --=20 You are receiving this mail because: You are on the CC list for the bug.=