From nobody Wed Jun 21 19:33:46 2023 X-Original-To: freebsd-arm@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 4QmYb83RXzz4gZyq; Wed, 21 Jun 2023 19:33:56 +0000 (UTC) (envelope-from grembo@freebsd.org) Received: from mail.evolve.de (mail.evolve.de [213.239.217.29]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA512 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mail.evolve.de", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4QmYb76gxqz4GNL; Wed, 21 Jun 2023 19:33:55 +0000 (UTC) (envelope-from grembo@freebsd.org) Authentication-Results: mx1.freebsd.org; none Received: by mail.evolve.de (OpenSMTPD) with ESMTP id ddaa929a; Wed, 21 Jun 2023 19:33:48 +0000 (UTC) Received: by mail.evolve.de (OpenSMTPD) with ESMTPSA id 67526c51 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 21 Jun 2023 19:33:48 +0000 (UTC) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable List-Id: Porting FreeBSD to ARM processors List-Archive: https://lists.freebsd.org/archives/freebsd-arm List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arm@freebsd.org Mime-Version: 1.0 (1.0) Subject: Re: -current dropping ssh connections From: Michael Gmelin In-Reply-To: Date: Wed, 21 Jun 2023 21:33:46 +0200 Cc: Mark Millard , freebsd-net@freebsd.org, freebsd-arm@freebsd.org Message-Id: <0EB8C74C-C8A0-43EA-8654-BA77E43C66C0@freebsd.org> References: To: bob prohaska X-Mailer: iPhone Mail (20F66) X-Rspamd-Queue-Id: 4QmYb76gxqz4GNL X-Spamd-Bar: ---- X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:24940, ipnet:213.239.192.0/18, country:DE] X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-ThisMailContainsUnwantedMimeParts: N > On 21. Jun 2023, at 20:03, bob prohaska wrote: >=20 > =EF=BB=BFOn Wed, Jun 21, 2023 at 10:45:25AM -0700, Mark Millard wrote: >>> On Jun 21, 2023, at 10:24, bob prohaska wrote: >>>=20 >>> I've got a Pi4 running -current that seems to selectively drop ssh conne= ctions. >>=20 >> Only when the ssh has text streaming over it? Even when it >> is idle? Any other types of context differences that lead >> to observable differences of some type related to the >> disconnects (vs. lack of them)? >=20 > I can't detect any consistent pattern. For a while I thought load on the > sshd-host end made a difference, but the latest disconnect was on an idle > system with serial console output the only traffic on the dropped connecti= on.=20 >=20 >>> Connections running a shell seem to stay up, but a session running tip t= o a >>> usb-serial adapter (FTDI TTL232R-3V3) seems go away within a few hours.=20= >>=20 >> The way that reads, ssh to a shell and then running tip in >> that shell would stay up. (Does it?) tip is being run >> without ssh running a shell? May be more detail about the >> two contexts of establishing the connection is needed here? >>=20 >=20 > No, other way 'round. In both cases an ssh connection was made which > started a shell. In one a tip session was started, which seems prone=20 > to dropping. In the other an active shell (typically running buildworld,=20= > or maybe idle) kept running. This makes me think (perhaps wrongly) that=20= > tip is involved with the disconnection. Both shells are started as a > regular user and then su-d to root. >=20 > I'm fairly confident this isn't a client-side or NAT problem, simply becau= se > there are a dozen or so other ssh sessions running from the ssh client to t= he > various Pi2/3/4 hosts in my collection which stay up basically until they'= re > taken down deliberately. >=20 > I seem to (vaguely) recall a discussion of ssh problems over NAT some mont= hs=20 > ago, something about tolerating misssing ts (timestamps?). Is that still p= ossible? You can check if systctl net.inet.tcp.tolerate_missing_ts=3D1. It should be set to 1 by default since 13.1, but maybe it=E2=80=99s differen= t in current. Best