https://bugzilla.novell.com/show_bug.cgi?id=791280 https://bugzilla.novell.com/show_bug.cgi?id=791280#c0 Summary: MTU only at 576 with cable internet provicer via dhcp (eth0) - regression in iscdhcpclient? Classification: openSUSE Product: openSUSE 12.1 Version: Final Platform: x86 OS/Version: openSUSE 12.1 Status: NEW Severity: Major Priority: P5 - None Component: Network AssignedTo: bnc-team-screening@forge.provo.novell.com ReportedBy: abittner@abittner.de QAContact: qa-bugs@suse.de Found By: --- Blocker: --- User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11 moved an opensuse box to 12.1/x86, latest updates applied, multiple ethernet cards and the internet provider changed from xdsl/pppoe to cableinternet via simple dhcpv4 on ethernet card (pcie/onboard, realtek) now I am wondering why my MTU for the eth0 interface that connects to the cable modem gets set to 576 according to my research that is the lowest common mtu value that is available according to various ethernet and dhcp specs. some research landed me over at some ubuntu/debian bugs talking about some bad dhcp script of the isc-dhcp-client, but which is supposedly fixed in isc-dhcp 4.2.2-1, but opensuse 12.1 has even newer? I didnt have the chance to mess with enforcing some different MTU value on this affected box, or bootup some other more recent opensuse 12.2 linux with that cable modem or even try a windows machine directly with the cable modem just to see if the mtu 576 is an issue there as well. I am currently only able to remotely access this machine, thats why I am trying to avoid to disabling the network by messing things up, maybe I can help more at a later time. so maybe anyone can look into this if the isc-dhcp is really buggy and unfixed with opensuse 12.1, and if those ubuntu/debian bugs with isc-dhcp are valid and legit and somehow went missing in opensuse or some regeression got re-introduced with a later isc-dhcp again? thanks for helping to sort this out. debian/ubuntu bugs: http://osdir.com/ml/ubuntu-bugs/2011-12/msg27989.html https://bugs.launchpad.net/ubuntu/+source/isc-dhcp/+bug/881558 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=638267 bug excerpt: ..... Bug Description the following lines of /sbin/dhclient-script fails to detect MTU of 576: ~$ grep -A1 -n 'lt 576' /sbin/dhclient-script 177:if [ -z "$new_interface_mtu" ] || [ "$new_interface_mtu" -lt 576 ]; then 178- new_interface_mtu='' The correct syntax is -le not -lt. This has also been reported in debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=638267 But should be a simple fix and not require a new package. The result of this error is that the MTU of an interface configured by DHCP is dropped down to 576. ..... Reproducible: Always Steps to Reproduce: 1. 2. 3. Actual Results: I am originally reporting this as the ethernet throughput on this cable internet connected box is rather very low and sluggish and very jumpy, ssh sessions for example are very erratic and weird, so that made me to looking for the reason for this behavior and I then came across those MTU 576 issues. But then again I was also thinking about some kernel/driver(realtek) issues or incompatibilities or similar. Not quite sure. tuxmachine:/sbin # grep 576 * dhclient-script: $(( $new_interface_mtu )) -lt 576 ] ; dhclient-script: # 68 is the minimal legal value, but 576 the real life minimum tuxmachine:/sbin # ls -lart dhc* -rwxr-xr-x 1 root root 76284 Oct 29 2011 dhcpcd -rwxr-x--- 1 root root 19771 Sep 17 13:41 dhclient-script -rwxr-xr-x 1 root root 1802884 Sep 17 13:41 dhclient lrwxrwxrwx 1 root root 8 Nov 14 14:51 dhclient6 -> dhclient rpm -aq | grep -i dhc dhcpcd-3.2.3-47.70.1.2.i586 dhcp-client-4.2.4.P2-0.6.13.1.i586 dhcp-4.2.4.P2-0.6.13.1.i586 tuxmachine:/sbin # rpm -qi dhcp Name : dhcp Version : 4.2.4.P2 Release : 0.6.13.1 Architecture: i586 Install Date: Wed Nov 14 14:50:27 2012 Group : Productivity/Networking/Boot/Servers Size : 1735945 License : BSD-3-Clause Signature : RSA/SHA256, Wed Sep 26 16:45:42 2012, Key ID b88b2fd43dbdc284 Source RPM : dhcp-4.2.4.P2-0.6.13.1.src.rpm Build Date : Mon Sep 17 13:41:41 2012 Build Host : build19 Relocations : (not relocatable) Packager : http://bugs.opensuse.org Vendor : openSUSE URL : http://www.isc.org/software/dhcp Summary : Common Files Used by ISC DHCP Software Description : This package contains common programs used by both the ISC DHCP server ("dhcp-server" package) and client ("dhcp-client") as the omshell and common manual pages. Authors: -------- Internet Systems Consortium, Inc. <info@isc.org> Distribution: openSUSE 12.1 tuxmachine:/sbin # cat /etc/SuSE-release openSUSE 12.1 (i586) VERSION = 12.1 CODENAME = Asparagus tuxmachine:/sbin # ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:xx:xx:xx:xx:xx inet addr:188.xxx.xxx.xxx Bcast:188.xxx.xxx.255 Mask:255.255.248.0 UP BROADCAST RUNNING MULTICAST MTU:576 Metric:1 RX packets:3346973 errors:0 dropped:0 overruns:0 frame:0 TX packets:1212233 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1193927023 (1138.6 Mb) TX bytes:191201024 (182.3 Mb) Interrupt:41 Base address:0xa000 ethtool eth0 Settings for eth0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Advertised pause frame use: Symmetric Receive-only Advertised auto-negotiation: Yes Link partner advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Link partner advertised pause frame use: Symmetric Receive-only Link partner advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: MII PHYAD: 0 Transceiver: internal Auto-negotiation: on Supports Wake-on: pumbg Wake-on: g Current message level: 0x00000033 (51) drv probe ifdown ifup Link detected: yes grep eth0 /var/log/boot.msg <6>[ 6.558160] r8169 0000:02:00.0: eth0: RTL8168b/8111b at 0xf7dde000, 00:xx:xx:xx:xx:xx, XID 18000000 IRQ 40 done eth0 device: Realtek Semiconductor Co., Ltd. RTL8111/8168B eth0 device: Realtek Semiconductor Co., Ltd. RTL8111/8168B -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.