From owner-freebsd-hackers@FreeBSD.ORG Thu Feb 14 11:09:34 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 7685C9F4 for ; Thu, 14 Feb 2013 11:09:34 +0000 (UTC) (envelope-from Devin.Teske@fisglobal.com) Received: from mx1.fisglobal.com (mx1.fisglobal.com [199.200.24.190]) by mx1.freebsd.org (Postfix) with ESMTP id 47E7E959 for ; Thu, 14 Feb 2013 11:09:34 +0000 (UTC) Received: from smtp.fisglobal.com ([10.132.206.16]) by ltcfislmsgpa06.fnfis.com (8.14.5/8.14.5) with ESMTP id r1EB9W6Y012478 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT); Thu, 14 Feb 2013 05:09:32 -0600 Received: from LTCFISWMSGMB21.FNFIS.com ([10.132.99.23]) by LTCFISWMSGHT05.FNFIS.com ([10.132.206.16]) with mapi id 14.02.0309.002; Thu, 14 Feb 2013 05:09:31 -0600 From: "Teske, Devin" To: Wojciech Puchar , "freebsd-hackers@freebsd.org" Subject: RE: rsh/rlogin strange behavior Thread-Topic: rsh/rlogin strange behavior Thread-Index: AQHOCp9xD1iNtGIRjUuq20A96tJlfZh5L3kp Date: Thu, 14 Feb 2013 11:09:31 +0000 Message-ID: <13CA24D6AB415D428143D44749F57D7201EA93B6@ltcfiswmsgmb21> References: , In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.132.253.120] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.9.8327, 1.0.431, 0.0.0000 definitions=2013-02-14_04:2013-02-14,2013-02-14,1970-01-01 signatures=0 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Feb 2013 11:09:34 -0000 On Thu, 14 Feb 2013, Wojciech Puchar wrote: > i use rsh/rlogin regularly within LAN and over encrypted tunnels > it works generally fine but have strange behavior >=20 > when i output long amount of text in console (eg. cat bigfile), where long > is like 20kB it >=20 > a) display part of it and hangs (i have to kill rlogin) - rarely > b) display part of it and rest is skipped. then i can work normally. >=20 >=20 > ssh doesn't have such a problem. >=20 > what is wrong? >=20 This sounds oddly like a bug we discovered back in the 4 days with rsh. We discovered a bug years ago when moving from FreeBSD-4.8 to 4.11 (with ma= ny back-ported drivers) that a combination of the em(4) driver (back-ported= from RELENG_6) and changes to libc ended up in the traces. We could easily replicate the issue in csh with: repeat 100 rsh date HINT: Set yourself up in /etc/hosts.equiv on for password-less entry Repeat about 5 or 6 times and then eventually the connection will hang and = you won't be able to make more connections for some time. Next step? Execute "netstat -an | less" and look for oddities (like a mass = pile of FIN_WAIT_2 connections). In our case (ymmv) the final ACK was not being sent leaving the client side= stacking up a bunch of connections that take msl.timeout time to expire (i= irc). If I do remember correctly the problem happened when the server was u= sing an em(4) driver. Our ultimate solution was to either switch critical servers to fxp(4) based= hardware or roll entire sites over to using key-based SSH (which may work = for you -- have you thought about giving ssh-keygen a try? that is, if you'= re using rsh for the convenience of password-less entry via hosts.equiv for= example). --=20 Devin _____________ The information contained in this message is proprietary and/or confidentia= l. If you are not the intended recipient, please: (i) delete the message an= d all copies; (ii) do not disclose, distribute or use the message in any ma= nner; and (iii) notify the sender immediately. In addition, please be aware= that any message addressed to our domain is subject to archiving and revie= w by persons other than the intended recipient. Thank you.