[linux] RHEL/CentOS 4 networking trouble
jnicol at backnine.org
Thu Jul 5 17:48:18 PDT 2007
(Sorry for the cross-post, I'm under the impression that the RHEL list
has not many members. Please let me know if I shouldn't do this.)
The boxen I'm currently working on are CentOS 4.5, I've encountered
this same problem in RHEL 4 (no suprise, they're basically the same
thing). They're identical hardware, with a pair of onboard NICs each,
using the e1000 driver.
What I'm trying to do is add an IP address to eth1. These are new
servers, eth1 has never previously been configured or even brought up.
After adding the IP, everything looks fine in ifconfig and the routing
table. However, the system refuses to send ANY traffic via eth1. Pings
result in "destination host unreachable". Arping does nothing. Using
tcpdump, I can see that ARP requests are not being sent. The ifconfig
TX counter shows 0, and the RX counter only shows the 49 broadcast
packets that came in while the device was in promiscuous mode (while
running tcpdump). The mac-address-table on the switch also does not
show eth1's MAC address, indicating it has not received a single
packet from the server.
I've tried this on two seperate boxes. The first one, I edited the
configuration file appropriately, and then ran 'ifup eth1' (the
The second one, I used 'ifconfig eth1 10.254.250.227 netmask
255.255.255.224'. Same results.
Has anyone run into this? Any ideas on how to debug this further, and
maybe even get it to work?
eth1 Link encap:Ethernet HWaddr 00:30:48:8E:B4:5D
inet addr:10.254.250.226 Bcast:10.254.250.255 Mask:255.255.255.224
inet6 addr: fe80::230:48ff:fe8e:b45d/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:49 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:3493 (3.4 KiB) TX bytes:0 (0.0 b)
Base address:0x6000 Memory:e0400000-e0420000
eth0: negotiated 100baseTx-FD, link ok
eth1: negotiated 100baseTx-FD, link ok
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