From owner-freebsd-net@FreeBSD.ORG Thu Feb 10 19:16:33 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 09229106566C for ; Thu, 10 Feb 2011 19:16:33 +0000 (UTC) (envelope-from jayb@zoe.braeburn.org) Received: from mail167.messagelabs.com (mail167.messagelabs.com [216.82.253.179]) by mx1.freebsd.org (Postfix) with ESMTP id B69AC8FC13 for ; Thu, 10 Feb 2011 19:16:32 +0000 (UTC) X-VirusChecked: Checked X-Env-Sender: jayb@zoe.braeburn.org X-Msg-Ref: server-10.tower-167.messagelabs.com!1297363791!27187982!1 X-StarScan-Version: 6.2.9; banners=-,-,- X-Originating-IP: [144.160.20.145] Received: (qmail 28410 invoked from network); 10 Feb 2011 18:49:51 -0000 Received: from sbcsmtp6.sbc.com (HELO mlpd192.enaf.sfdc.sbc.com) (144.160.20.145) by server-10.tower-167.messagelabs.com with DHE-RSA-AES256-SHA encrypted SMTP; 10 Feb 2011 18:49:51 -0000 Received: from enaf.sfdc.sbc.com (localhost.localdomain [127.0.0.1]) by mlpd192.enaf.sfdc.sbc.com (8.14.4/8.14.4) with ESMTP id p1AIoEXc025723 for ; Thu, 10 Feb 2011 13:50:14 -0500 Received: from alpd052.aldc.att.com (alpd052.aldc.att.com [130.8.42.31]) by mlpd192.enaf.sfdc.sbc.com (8.14.4/8.14.4) with ESMTP id p1AIoBoW025682 for ; Thu, 10 Feb 2011 13:50:11 -0500 Received: from aldc.att.com (localhost.localdomain [127.0.0.1]) by alpd052.aldc.att.com (8.14.4/8.14.4) with ESMTP id p1AInmSa029797 for ; Thu, 10 Feb 2011 13:49:48 -0500 Received: from oz.mt.att.com (oz.mt.att.com [135.16.165.23]) by alpd052.aldc.att.com (8.14.4/8.14.4) with ESMTP id p1AIngPL029583 for ; Thu, 10 Feb 2011 13:49:43 -0500 Received: by oz.mt.att.com (Postfix, from userid 500) id 853662BF2C; Thu, 10 Feb 2011 13:49:42 -0500 (EST) X-Mailer: emacs 21.2.1 (via feedmail 8 I); VM 7.18 under Emacs 21.2.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <19796.13124.805432.342309@oz.mt.att.com> Date: Thu, 10 Feb 2011 13:49:40 -0500 From: Jay Borkenhagen To: freebsd-net@freebsd.org X-GPG-Fingerprint: DDDB 542E D988 94D0 82D3 D198 7DED 6648 2308 D3C0 Sender: jayb@zoe.braeburn.org Subject: cannot set mtu > 1500 on em0 optical Gig-E X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Jay Borkenhagen List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Feb 2011 19:16:33 -0000 Hi, For quite a while now it appears that mtu on my gigabit ethernet fiber em0 cards cannot be configured higher than the default 1500 bytes. Here's what I get when I attempt to set it lower and higher on a brand new 8.2-RC3 box: === sandbox# uname -v FreeBSD 8.2-RC3 #0: Sun Jan 30 06:52:51 UTC 2011 root@almeida.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC sandbox# sandbox# ifconfig em0 em0: flags=8843 metric 0 mtu 1500 options=18 ether 00:d0:b7:7c:f8:01 inet 10.1.2.3 netmask 0xffffff00 broadcast 10.1.2.255 media: Ethernet autoselect status: no carrier sandbox# ifconfig em0 mtu 1499 sandbox# ifconfig em0 | grep mtu em0: flags=8843 metric 0 mtu 1499 sandbox# ifconfig em0 mtu 1501 ifconfig: ioctl (set mtu): Invalid argument sandbox# ifconfig em0 | grep mtu em0: flags=8843 metric 0 mtu 1499 sandbox# ifconfig em0 mtu 1500 sandbox# ifconfig em0 | grep mtu em0: flags=8843 metric 0 mtu 1500 sandbox# sandbox# pciconf -lv | sed -n '/em0@/,/em1/p' em0@pci0:0:2:0: class=0x020000 card=0x10008086 chip=0x10008086 rev=0x03 hdr=0x00 vendor = 'Intel Corporation' device = '82542 Gigabit Ethernet Controller' class = network subclass = ethernet em1@pci0:0:4:0: class=0x020000 card=0x10008086 chip=0x10008086 rev=0x03 hdr=0x00 sandbox# === However, back in the 6.2 days it allowed it: === [jayb@cactus ~]$ uname -v FreeBSD 6.2-PRERELEASE #0: Tue Dec 26 16:53:18 EST 2006 root@cactus.iplabs.att.com:/usr/obj/usr/src/sys/CACTUS [jayb@cactus ~]$ [jayb@cactus ~]$ ifconfig em0 em0: flags=8843 mtu 1500 options=8 inet 10.0.1.152 netmask 0xfffffffc broadcast 10.0.1.155 ether 00:90:27:e3:0a:67 media: Ethernet autoselect status: no carrier [jayb@cactus ~]$ [jayb@cactus ~]$ sudo ifconfig em0 mtu 9000 [jayb@cactus ~]$ ifconfig em0 | grep mtu em0: flags=8843 mtu 9000 [jayb@cactus ~]$ [jayb@cactus ~]$ pciconf -lv | sed -n '/em0@/,/none0@/p' em0@pci0:2:0: class=0x020000 card=0x10008086 chip=0x10008086 rev=0x02 hdr=0x00 vendor = 'Intel Corporation' device = '82542 Gigabit Ethernet Controller' class = network subclass = ethernet none0@pci0:4:0: class=0x088000 card=0x0767101e chip=0x9063101e rev=0x04 hdr=0x00 [jayb@cactus ~]$ === Can this be made to work again? Thanks. Jay B.