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