When I do an ethtool command I get:
[root@linux2 /]# ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
Advertised auto-negotiation: Yes
Current message level: 0x00000001 (1)
Link detected: yes
But when I run Tcpdump I get this:
[root@linux2 /]# tcpdump -C 1 -w dumptest
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
12 packets captured
12 packets received by filter
0 packets dropped by kernel
In ethtool it says I am running at 100MB but tcpdump says the link-type is 10MB. Which one is the real one and how do I set them the same. The further problem is this. I have a linksys hub. When sniffing in promiscuous mode, the hub is only sending data directed towards the machine in question. All other traffic is not being broadcast from the hub to the sniffing machine. I think this is due to some sort of limitation on linksys's part. They say on their website...
"The Linksys hubs only operate at Half-Duplex speed and they broad cast a packet to all the nodes on the network (the Auto- sensing hubs broadcast the 10Mb packets to the port that operate at 10Mb only and broadcast the 100Mb packets to the ports that operate at 100Mb only."
So essentially if the the nic in the linux box is listening at 10MB, it will not hear anything coming from a 100MB connection on a 10/100MB hub. I need to make sure the nic is listening at 100MB or set it to do so.