From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 29 21:21:29 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5038816A4CE for ; Mon, 29 Nov 2004 21:21:29 +0000 (GMT) Received: from rproxy.gmail.com (rproxy.gmail.com [64.233.170.198]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6602443D49 for ; Mon, 29 Nov 2004 21:21:27 +0000 (GMT) (envelope-from dr.clau@gmail.com) Received: by rproxy.gmail.com with SMTP id a36so445133rnf for ; Mon, 29 Nov 2004 13:21:25 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:return-path:message-id:disposition-notification-to:date:from:user-agent:x-accept-language:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:x-enigmail-supports:content-type; b=EeYffCaRgMmQHOAeBJ1SYkbjCypwLKdw6+LfPfMOkXigTlYyaqi32mxA5CAnnW7s9mf7N9CK76tKsEx/yKzZK1VsoOzjF30qBj7KvnNgShtGS3eip6+X5hKngKsiibB4BBcwCXARdd0CAw+YQdpiPR8lFix6Qug3I5XlXR3FYVw= Received: by 10.38.77.63 with SMTP id z63mr117320rna; Mon, 29 Nov 2004 13:21:24 -0800 (PST) Received: from ?82.79.29.15? ([82.79.29.15]) by smtp.gmail.com with ESMTP id 70sm11174rnc; Mon, 29 Nov 2004 13:21:24 -0800 (PST) Message-ID: <41AB926F.30003@gmail.com> Date: Mon, 29 Nov 2004 23:19:43 +0200 From: Claudiu Dragalia-Paraipan User-Agent: Mozilla Thunderbird 0.9 (X11/20041125) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andre Oppermann References: <41AA0043.5070109@gmail.com> <20041129185152.GF804@cirb503493.alcatel.com.au> <41AB84A6.50309@freebsd.org> In-Reply-To: <41AB84A6.50309@freebsd.org> X-Enigmail-Version: 0.89.0.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig07BB196C97858DA16AF839F1" cc: Peter Jeremy cc: hackers@freebsd.org cc: current@freebsd.org Subject: Re: ssh & select() problem on 5.3 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Nov 2004 21:21:29 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig07BB196C97858DA16AF839F1 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Andre Oppermann wrote: > Peter Jeremy wrote: > >> On Sun, 2004-Nov-28 18:43:47 +0200, Claudiu Dragalia-Paraipan wrote: >> >>> Since the problem occurs only when I connect to the firewall or to a >>> server behind it, I started to suspect a hardware failure. Could a >>> network card cause such problems ? >> >> >> A couple of people have mentioned path-MTU problems. I've also bumped >> into this problem when playing with VLANs where one end of the VLAN >> trunk doesn't support long frames - an oversize packet will get ignored >> by the receiver without any error being returned. > > > If the oversized ethernet frame makes it to the FreeBSD box it will drop > the frame in the ethernet hardware or in ether_input() with a message. If > you don't get a message on the console you have to look at the driver > statistics if it got any oversized frames. > > If the switches along the patch can't handle the oversized frame they will > simply drop it. No way to work around that. > When the MTU is set to a value below 1500, for example 1450, I get this messages: Nov 29 23:02:34 firewall kernel: rl0: discard oversize frame (ether type 800 flags 3 len 1466 > max 1464) Nov 29 23:03:00 firewall kernel: rl0: discard oversize frame (ether type 800 flags 3 len 1514 > max 1464) ... and much many of them. With MTU 1500 I didn't notice any such message in logs. So, can I safely assume that the problem occurs because somewhere packets are simply dropped, without any warning ? -- Claudiu Dragalina-Paraipan dr.clau@gmail.com --------------enig07BB196C97858DA16AF839F1 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFBq5Jvm0FWxb+swkQRAuCdAJ9rm+kLUMtczXxU6u9BJ560p13YQgCfcmyO M7Vj5ns5mS/Njs5t5uZuYx8= =WLTQ -----END PGP SIGNATURE----- --------------enig07BB196C97858DA16AF839F1--