We’ve talked about IPv6, we’ve talked about broadcast and other parts of the ifconfig output, but there’s more ifconfig output to look at.   The rest of the story, as it were.  So we have this output:

eth0      Link encap:Ethernet  HWaddr 00:1A:2B:3C:00:00
          inet addr:192.168.0.10  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fd91:ae3b:d5e8:aa85:0:0:0:0 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:41620 errors:0 dropped:0 overruns:0 frame:0
          TX packets:40231 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:21601203 (20.6 MiB)  TX bytes:6145876 (5.8 MiB)
          Interrupt:21 Base address:0xe000

eth0 is the interface for your computer to the internet.  That thing that all the traffic goes through.  That means that there’s Internet traffic going through that device.   ifconfig shows us more information than just the IP address.

Let’s skip to these two lines:

          RX packets:41620 errors:0 dropped:0 overruns:0 frame:0
          TX packets:40231 errors:0 dropped:0 overruns:0 carrier:0

The Internet breaks all traffic up into packages called packets.  Think of it like a really really long text.   Every 160 characters in your text, your phone will send along the message and wait for the next bit.  (That 160 characters depends on your phone.  It could be more, it could be less.)  Your computer does the same thing.  It takes your messages and breaks them into chunks and sends it through the Interface.  It can also receive things through the interface.

The RX packets packages string in the ifconfig output is the number of packets your computer received and the TX packets is the number of packets your computer transmits.

Now these lines:

RX bytes:21601203 (20.6 MiB)  TX bytes:6145876 (5.8 MiB)

Are the total amount of traffic that went through all those pipes.  We received 20.6 megabytes of data and we sent out 5.8 megabytes of data.  We were busy surfing the web and pulled down the fun stuff.

The last bit of the output that we’re going to talk about is this line:

collisions:0 

A collision occurs when two devices on the same network try to transmit at the same time.  ifconfig keeps track of this because it usually means that there’s something wrong with the network and it should be looked at.

Now we’ve discussed all the important parts of the network interface!  If you want more information, read this site.