Red Hat Bugzilla – Bug 87859
(NET) ethtool does not detect link on connected ethernet device
Last modified: 2013-07-02 22:10:45 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 Galeon/1.2.0 (X11; Linux i686; U;) Gecko/20020408
Description of problem:
ethtool incorrectly states 'link detected: no', even though the etherne t is
connected and up.
As a consequence DHCP configuration fails, since
/etc/sysconfig/network-scripts/ifup queries ethtool via check_link_down. Static
configuration succeeds and as a workaround I can get DHCP working as well if I
comment out the check_link_down call.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. have an ethernet device installed (eth0)
2. ethtool eth0
3. ifconfig eth0
4. ping 10.88.2.1
Actual Results: sh-2.05b# ethtool eth0
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
Supportes auto-negotiation: Yes
Advertised link modes: Not reported
Advertised auto-negotiation: No
Current message level: 0x00000001 (1)
Link detected: no
sh-2.05# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:50:56:D4:22:68
inet addr:10.88.2.128 Bcast:10.88.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:10 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:1524 (1.4 Kb) TX bytes:1348 (1.3 Kb)
Interrupt:10 Base address:0x10a0
sh-2.05# ping 10.88.2.1
PING 10.88.2.1 (10.88.2.1) 56(84) bytes of data.
64 bytes from 10.88.2.1: icmp_seq=1 ttl=64 time=1.28 ms
Expected Results: Clearly the link is OK, so ethtool should detect it.
The tested configurations are VMware guest installs on VMware GSX 2.5 servers
(running on RH8.0 and RH7.3). eth0 is detected as PCnet/PCI II 79C970A and has
been configured for 'bridged networking' in VMware in one case and 'host only
networking' in the other.
The problem does not occur with RH8.0 running on the same VMware installations.
Also reporting this behavior.
This same situation happens, if you try to run RedHat Linux 9 in VMware 4 as
GuestOS. Once you get rid of ethtool, things start working as they should be.
What ethernet driver(s) are being used?
ethtool requires link-detection support in the kernel driver.
Thanks for the bug report. However, Red Hat no longer maintains this version of
the product. Please upgrade to the latest version and open a new bug if the problem
The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases,
and if you believe this bug is interesting to them, please report the problem in
the bug tracker at: http://bugzilla.fedora.us/