NIC speed and mode of communication

[Ankit Madan]

Can anyone tell me how to calculate the ethernet card speed and mode of communication(Full Duplex/Half Duplex) and collision rate if I am not the root user. I know about ethtool and mii-tool but they can't run as a normal user.

[Steven E. Protter]

Shalom,

Always helps to know the distribution of Linux.

You need to look into a tool called sudo, which will let you authorize these two tools for non-root users.

Here you go:
[root@prottervm ~]# mii-tool eth0
eth0: negotiated 100baseTx-FD, link ok
[root@prottervm ~]# ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Current message level: 0x00000007 (7)
Link detected: yes

SEP

[Matti_Kurkela · Accepted solution]

You can get the number of collisions by reading the appropriate sysfs file for your NIC. For example, eth0:

cat /sys/class/net/eth0/statistics/collisions

If your system uses a 2.4.xx or older kernel, the /sys virtual filesystem does not exist in it. In that case, you can run the ifconfig command with no options as a regular user, specifying an absolute path:

/sbin/ifconfig eth0

As far as I know, there is no way to get the speed/duplex information without root privileges.

However, if the number of collisions is exactly 0 and the system has been running for a while, the system is either in a _very_ low-traffic network or has been configured for full duplex. (Full duplex = the "transmit" and "receive" wires are completely independent, so the collision detection is switched off.)

MK