Make sure the driver is communicating properly with the hardware

Use the nicinfo utility to check if you're receiving and sending packets. If you aren't receiving packets on a high-traffic network, the driver and the hardware might not be communicating.

Here's some typical output from the nicinfo command:

Physical Node ID ........................... 000102 C510D4
Current Physical Node ID ................... 000102 C510D4
Current Operation Rate ..................... 100.00 Mb/s full-duplex
Active Interface Type ...................... MII
Active PHY Address ......................... 3
Power Management State ..................... Active
Maximum Transmittable data Unit ............ 1514
Maximum Receivable data Unit ............... 1514
Receive Checksumming Enabled ............... TCPv6
Transmit Checksumming Enabled .............. TCPv6
Hardware Interrupt ......................... 0x5
DMA Channel ................................ 0
I/O Aperture ............................... 0xd400 - 0xd47f
ROM Aperture ............................... 0
Memory Aperture ............................ 0xe6000000 - 0xe6000FFF
Promiscuous Mode ........................... Off
Multicast Support .......................... Enabled

Packets Transmitted OK ..................... 104
Bytes Transmitted OK ....................... 10067
Broadcast Packets Transmitted OK ........... 6
Multicast Packets Transmitted OK ........... 1
Memory Allocation Failures on Transmit ..... 0

Packets Received OK ........................ 1443
Bytes Received OK .......................... 168393
Broadcast Packets Received OK .............. 427970
Multicast Packets Received OK .............. 37596
Memory Allocation Failures on Receive ...... 0

Single Collisions on Transmit .............. 0
Multiple Collisions on Transmit ............ 0
Deferred Transmits ......................... 0
Late Collision on Transmit errors .......... 0
Transmits aborted (excessive collisions) ... 0
Transmits aborted (excessive deferrals) .... 0
Transmit Underruns ......................... 0
No Carrier on Transmit ..................... 0
Jabber detected ............................ 0
Receive Alignment errors ................... 0
Received packets with CRC errors ........... 0
Packets Dropped on receive ................. 0
Ethernet Headers out of range .............. 0
Oversized Packets received ................. 0
Frames with Dribble Bits ................... 0
Total Frames experiencing Collision(s) ..... 0
Note: The output from nicinfo depends on what the driver supports; not all fields are included for all drivers. However, the output always includes information about the bytes and packets that were transmitted and received.

The categories shown in the above example are described below. When dealing with a network problem, start with these: