Dell Intel PRO Family of Adapters - Manual (Page 100)

Driver Compilation
When trying to compile the driver by running make install, the following error may occur: "Linux kernel source not con-
figured - missing version.h"
To solve this issue, create the version.h file by going to the Linux source tree and entering:
make include/linux/version.h
Do Not Use LRO when Routing Packets
Due to a known general compatibility issue with LRO and routing, do not use LRO when routing packets.
Performance Degradation with Jumbo Frames
Degradation in throughput performance may be observed in some Jumbo frames environments. If this is observed,
increasing the application's socket buffer size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help.
For more details, see the specific application documentation in the text file ip-sysctl.txt in your kernel documentation.
Multiple Interfaces on Same Ethernet Broadcast Network
Due to the default ARP behavior on Linux, it is not possible to have one system on two IP networks in the same Eth-
ernet broadcast domain (non-partitioned switch) behave as expected. All Ethernet interfaces will respond to IP traffic for
any IP address assigned to the system. This results in unbalanced receive traffic.
If you have multiple interfaces in a server, turn on ARP filtering by entering:
echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter
(this only works if your kernel's version is higher than 2.4.5), or install the interfaces in separate broadcast domains.
UDP Stress Test Dropped Packet Issue
Under small packets UDP stress test with the 10GbE driver, the Linux system may drop UDP packets due to the full-
ness of socket buffers. You may want to change the driver's Flow Control variables to the minimum value for controlling
packet reception.
Another option is to increase the kernel's default buffer sizes for udp by changing the values in /proc/sys/net/-
core/rmem_default and rmem_max.
Unplugging Network Cable While ethtool -p is Running
In kernel versions 2.5.50 and later (including 2.6 kernel), unplugging the network cable while ethtool -p is running will
cause the system to become unresponsive to keyboard commands, except for control-alt-delete. Restarting the system
appears to be the only remedy.
Cisco Catalyst 4948-10GE Switch Running ethtool -g May Cause Switch to Shut
Down Ports
82598-based hardware can re-establish link quickly and when connected to some switches, rapid resets within the
driver may cause the switch port to become isolated due to "link flap". This is typically indicated by a yellow instead of a
green link light. Several operations may cause this problem, such as repeatedly running ethtool commands that cause
a reset.
A potential workaround is to use the Cisco IOS command "no errdisable detect cause all" from the Global Configuration
prompt which enables the switch to keep the interfaces up, regardless of errors.
MSI-X Issues with Kernels Between 2.6.19 and 2.6.21 (inclusive)
Kernel panics and instability may be observed on any MSI-X hardware if you use irqbalance with kernels between
2.6.19 and 2.6.21. If these types of problems are encountered, you may disable the irqbalance daemon or upgrade to a
newer kernel.