From owner-freebsd-bugs@FreeBSD.ORG Sat Aug 11 01:20:04 2007 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7057816A41A for ; Sat, 11 Aug 2007 01:20:04 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 3AC6D13C465 for ; Sat, 11 Aug 2007 01:20:04 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.1/8.14.1) with ESMTP id l7B1K4EB055818 for ; Sat, 11 Aug 2007 01:20:04 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.1/8.14.1/Submit) id l7B1K4P4055817; Sat, 11 Aug 2007 01:20:04 GMT (envelope-from gnats) Resent-Date: Sat, 11 Aug 2007 01:20:04 GMT Resent-Message-Id: <200708110120.l7B1K4P4055817@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Jacek Zapala Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EEF9216A41A for ; Sat, 11 Aug 2007 01:15:55 +0000 (UTC) (envelope-from nobody@FreeBSD.org) Received: from www.freebsd.org (www.freebsd.org [IPv6:2001:4f8:fff6::21]) by mx1.freebsd.org (Postfix) with ESMTP id E00D613C428 for ; Sat, 11 Aug 2007 01:15:55 +0000 (UTC) (envelope-from nobody@FreeBSD.org) Received: from www.freebsd.org (localhost [127.0.0.1]) by www.freebsd.org (8.14.1/8.14.1) with ESMTP id l7B1Fs80063451 for ; Sat, 11 Aug 2007 01:15:54 GMT (envelope-from nobody@www.freebsd.org) Received: (from nobody@localhost) by www.freebsd.org (8.14.1/8.14.1/Submit) id l7B1Fsum063450; Sat, 11 Aug 2007 01:15:54 GMT (envelope-from nobody) Message-Id: <200708110115.l7B1Fsum063450@www.freebsd.org> Date: Sat, 11 Aug 2007 01:15:54 GMT From: Jacek Zapala To: freebsd-gnats-submit@FreeBSD.org X-Send-Pr-Version: www-3.1 Cc: Subject: kern/115413: ipv6 pmtu not working X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Aug 2007 01:20:04 -0000 >Number: 115413 >Category: kern >Synopsis: ipv6 pmtu not working >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sat Aug 11 01:20:02 GMT 2007 >Closed-Date: >Last-Modified: >Originator: Jacek Zapala >Release: 6.2 >Organization: >Environment: FreeBSD xxxxx 6.2-RELEASE FreeBSD 6.2-RELEASE #0: Wed Apr 25 13:06:39 CEST 2007 root@xxxxxx:/usr/src/sys/i386/compile/DELL_2950 i386 >Description: IPv6 path MTU discovery does not work. ICMP6 "packet too big" messages arrive, but seem to be ignored (tcp segment with unmodified mtu is retransmitted). Instead, tcp "discarded for bad checksums" counter gets incremented (could be a coincidence?) Checksum for incoming ICMPv6 packet is ok (according to wireshark), checksum of tcp packet included in ICMPv6 message is of course wrong (as not whole original packet fits into 1280 bytes long ICMPv6 message). Interface: bce0: flags=8843 mtu 1500 options=3b Destination address is normal, unicast address (problem was noticed when sendmail could not send mail to some destinations). Reboot didn't help ;-) As a workaround I have set 1280 bytes mtu for default ipv6 route. >How-To-Repeat: >Fix: >Release-Note: >Audit-Trail: >Unformatted: