Date: Thu, 14 Feb 2013 11:09:31 +0000 From: "Teske, Devin" <Devin.Teske@fisglobal.com> To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>, "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: RE: rsh/rlogin strange behavior Message-ID: <13CA24D6AB415D428143D44749F57D7201EA93B6@ltcfiswmsgmb21> In-Reply-To: <alpine.BSF.2.00.1302141135570.1901@wojtek.tensor.gdynia.pl> References: <alpine.BSF.2.00.1302131837470.1552@wojtek.tensor.gdynia.pl>, <alpine.BSF.2.00.1302141135570.1901@wojtek.tensor.gdynia.pl>
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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 <host> date HINT: Set yourself up in /etc/hosts.equiv on <host> 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.
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