From Mark.Martinec@ijs.si Fri Feb 19 18:04:21 2016 MIME-Version: 1.0 X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD autolearn=ham autolearn_force=no version=3.4.0 X-Sender: Mark.Martinec@ijs.si Message-ID: <14b84068e4cbfef4b6149418a019d8d7@mailbox.ijs.si> content-type: text/plain; charset="utf-8"; format="flowed" X-Virus-Scanned: amavisd-new at ijs.si Organization: Jozef Stefan Institute Received: from mx.pao1.isc.org (mx.pao1.isc.org [IPv6:2001:4f8:0:2::2b]) by bugs.isc.org (Postfix) with ESMTP id 2F1B771B5AA for ; Fri, 19 Feb 2016 18:04:21 +0000 (UTC) Received: from mail.ijs.si (mail.ijs.si [IPv6:2001:1470:ff80::25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx.pao1.isc.org (Postfix) with ESMTPS id 19FA2349508 for ; Fri, 19 Feb 2016 18:04:18 +0000 (UTC) Received: from amavis-ori.ijs.si (localhost [IPv6:::1]) by mail.ijs.si (Postfix) with ESMTP id 3q6LQ606HrzZJ for ; Fri, 19 Feb 2016 19:04:14 +0100 (CET) Received: from mail.ijs.si ([IPv6:::1]) by amavis-ori.ijs.si (mail.ijs.si [IPv6:::1]) (amavisd-new, port 10026) with LMTP id UI-agPmtHbVS for ; Fri, 19 Feb 2016 19:04:10 +0100 (CET) Received: from mildred.ijs.si (mailbox.ijs.si [IPv6:2001:1470:ff80::143:1]) by mail.ijs.si (Postfix) with ESMTP id 3q6LQ265gyzZG for ; Fri, 19 Feb 2016 19:04:09 +0100 (CET) Received: from nabiralnik.ijs.si (nabiralnik.ijs.si [IPv6:2001:1470:ff80::80:16]) by mildred.ijs.si (Postfix) with ESMTP id 3q6LQ14VV8ztb for ; Fri, 19 Feb 2016 19:04:09 +0100 (CET) Received: from neli.ijs.si (2001:1470:ff80:88:21c:c0ff:feb1:8c91) by webmail.ijs.si with HTTP (HTTP/1.1 POST); Fri, 19 Feb 2016 19:04:09 +0100 Delivered-To: dhcp-bugs@bugs.isc.org User-Agent: Roundcube Webmail/1.1.4 Subject: "bad udp checksums in packets" in isc-dhcpd-4.3.3-P1 @ FreeBSD Return-Path: X-Original-To: dhcp-bugs@bugs.isc.org Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ijs.si; h= user-agent:message-id:organization:subject:subject:from:from :date:date:content-transfer-encoding:content-type:content-type :mime-version:received:received:received:received; s=jakla4; t= 1455905050; x=1458497051; bh=ynoSaMlOmj1jViz4+twDs63G1vjw1tllCxf cwv7x33k=; b=MRv+qPy8f6zi5g50dO0bIq9bjEqAGIRSh0osDbgpFJ98F8OWXYw hGlQc9B2uDgPrAJYa2SuuqUdh+e1NiYG2EdimhjL05JhBANOLMUogKmZ5LP9h/7N MxS/B5fCNs6lP1neRtl4kSDUMHx8NYo5yk5Wgy/gtkacs4iYA3FbdnsY= Date: Fri, 19 Feb 2016 19:04:09 +0100 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on mx.pao1.isc.org To: dhcp-bugs@isc.org Content-Transfer-Encoding: 7bit From: "Mark Martinec" X-RT-Original-Encoding: ascii X-RT-Interface: Email Content-Length: 2477 Using isc-dhcpd-4.3.3-P1 from FreeBSD ports, on an amd64 host (Intel Xeon), running FreeBSD 10.3-BETA2. The ethernet interface driver is igb, GbE NIC is Intel PRO/1000 Network Connection version - 2.4.0. The dhcpd server (in IPv4 mode) is running on a physical machine, there is *no* virtualization involved, nor a jail or VIMAGE a host firewall. While it seems that most clients successfully communicate with a dhcpd server, I can see a steady trickle of log entries like: Feb 19 14:26:06 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:06 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:07 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:08 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:08 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:14 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:14 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:14 dhcp2 dhcpd: 4 bad udp checksums in 5 packets Feb 19 14:26:14 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:18 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:19 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:34 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:36 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:36 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:36 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:36 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:36 dhcp2 dhcpd: 4 bad udp checksums in 7 packets Feb 19 14:26:36 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:36 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:36 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:39 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:40 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Feb 19 14:26:40 dhcp2 dhcpd: 3 bad udp checksums in 5 packets Other services on this host have no problem with communication, netstat -I igb0 does not show any I/O errors on the interface. Note that this dhcpd server sees both the proxied as well as link-local client requests. Disabling checksum offloading on the NIC avoids the problem! (ifconfig igb0 -rxcsum). I can see that a recent release of isc-dhcpd-4.3 received a bunch of workarounds for just this kind of a problem, although these all concentrated on Linux or on virtualizes network interfaces. Seems the same problem still persists on a FreeBSD platform. Mark