From nobody Wed Jun 21 17:24:14 2023 X-Original-To: freebsd-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 4QmVjP1CCMz4gqMW; Wed, 21 Jun 2023 17:24:09 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Received: from www.zefox.net (www.zefox.net [50.1.20.27]) (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 (2048 bits) client-digest SHA256) (Client CN "www.zefox.com", Issuer "www.zefox.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4QmVjN17pbz3QDM; Wed, 21 Jun 2023 17:24:08 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Authentication-Results: mx1.freebsd.org; dkim=none; spf=none (mx1.freebsd.org: domain of fbsd@www.zefox.net has no SPF policy when checking 50.1.20.27) smtp.mailfrom=fbsd@www.zefox.net; dmarc=none Received: from www.zefox.net (localhost [127.0.0.1]) by www.zefox.net (8.17.1/8.15.2) with ESMTPS id 35LHOE7P056488 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Wed, 21 Jun 2023 10:24:15 -0700 (PDT) (envelope-from fbsd@www.zefox.net) Received: (from fbsd@localhost) by www.zefox.net (8.17.1/8.15.2/Submit) id 35LHOEGC056487; Wed, 21 Jun 2023 10:24:14 -0700 (PDT) (envelope-from fbsd) Date: Wed, 21 Jun 2023 10:24:14 -0700 From: bob prohaska To: freebsd-net@freebsd.org, freebsd-arm@freebsd.org Subject: -current dropping ssh connections Message-ID: 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 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spamd-Result: default: False [-0.59 / 15.00]; AUTH_NA(1.00)[]; NEURAL_HAM_LONG(-1.00)[-0.998]; NEURAL_HAM_MEDIUM(-1.00)[-0.998]; NEURAL_HAM_SHORT(-1.00)[-0.998]; WWW_DOT_DOMAIN(0.50)[]; SUBJECT_ENDS_SPACES(0.50)[]; MID_RHS_WWW(0.50)[]; MIME_GOOD(-0.10)[text/plain]; FROM_EQ_ENVFROM(0.00)[]; ASN(0.00)[asn:7065, ipnet:50.1.16.0/20, country:US]; R_DKIM_NA(0.00)[]; MLMMJ_DEST(0.00)[freebsd-net@freebsd.org,freebsd-arm@freebsd.org]; R_SPF_NA(0.00)[no SPF record]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_TWO(0.00)[2]; RCVD_COUNT_THREE(0.00)[3]; DMARC_NA(0.00)[zefox.net]; ARC_NA(0.00)[]; RCVD_TLS_LAST(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_NONE(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[] X-Rspamd-Queue-Id: 4QmVjN17pbz3QDM X-Spamd-Bar: / X-ThisMailContainsUnwantedMimeParts: N I've got a Pi4 running -current that seems to selectively drop ssh connections. Connections running a shell seem to stay up, but a session running tip to a usb-serial adapter (FTDI TTL232R-3V3) seems go away within a few hours. There don't seem to be any error messages on the console at all, the client session simply reports client_loop: send disconnect: Broken pipe Searches through /var/log/sshd_debug.log find many transactions between the ssh client and the -current target host, but none seem to be error messages; all are either connection reports or disconnects by user. This sort of behavior has been intermittent with aarch64 among both the Pi4 and a pair of Pi3s for some time, but now only the Pi4 is dropping connections. I've tried searching /var/log/sshd_debug.log for the keywords tip, ucom, the IP address of the NAT client used to connect and cuaU0. Are there other things worth looking for? Right now I'm using in /etc/rc.conf the line sshd_flags="-E /var/log/sshd_debug.log" which is already quite verbose. Is there a better option that emphasizes errors over normal traffic? Thanks for reading, bob prohaska