Network configuration in FreeBSD

[Giorgos Keramidas]

On 2008-01-28 21:03, Bhuvaneswari Ramkumar <ramkumar at iastate.edu> wrote:
> ok here u go, the exact output of the the commands:

Excellent!  Thank you :-)

> #ifconfig -a
> 
> em0: flags=8802<BROADCAST, SIMPLEX, MULTICAST> mtu 1500
> options=b<RXSCUM, TXSCUM, VLAN_MTU>
> ether :0d:56:f0:f1:ba
> media:Ethernet autoselect (100baseTX <full-duplex>)
> status: active
> 
> plip0:flags=108810<POINTTOPOINT,SIMPLEX,MULTICAST> mtu 1500
> lo0:flags=8049<UP, LOOPBACK,RUNNING,MULTICAST> MTU 16384
> inet 127.0.0.1 netmask 0xff000000
> inet ::1 prefixlen 128
> inet6 fe80 :: 1% lo0 prefixlen 64 scopeid 0x3

See the `active' status and the `media' description?  This means you
have a network cable connected and FreeBSD has autodetected that you are
using a full-duplex 100 Mbit/s link.

That's good :)

On 2008-01-28 21:10, Bhuvaneswari Ramkumar <ramkumar at iastate.edu> wrote:
> the netstat reads:
> 
> #netstat -nr
> 
> Routing tables
> 
> Internet:
> Destination Gateway  Flags  REfs  Use Netif     Expire
> 127.0.0.1     127.0.0.1   UH        0    41     lo0
> 
> 
> Internet 6
> 
> Destination          Gateway          Flags   Netif
> Expire
> ::1                            ::1                   UH       lo0
> fe80::%lo0/64       fe80::1%lo0        U         lo0
> fe80::1%lo0           link#3                 UHL     lo0
> ff01::/32                    ::1                      U        lo0
> ff02 :: %lo0/32          ::1                    UC          lo0

Hmmm.  There seems to be something very 'odd' about your interfaces.

	* There is no `lo0' loopback interface, which commonly uses the
	  127.0.0.1 address.

	* The 127.0.0.1 address is assigned to plip0 (IP over parallel
	  port), which seems wrong.

	* The em0 interface has no address.

Can you try the following commands, so see if you can *manually* set up
the interfaces?

1. Bringing down the 'plip0 interface
-------------------------------------

	# ifconfig plip0 unplumb

This should bring down and delete the plip0 interface.  You don't really
need it when em0 starts working.

2. Bringing up the `lo0' loopback interface
-------------------------------------------

	# ifconfig lo0 inet 127.0.0.1/32 up

This will bring up the `lo0' interface, with the correct address.

3. Bringing up the em0 interface
--------------------------------

Finally, try bringing up the `em0' interface with dhclient OR ifconfig.
You don't need *both*.  One of them should be sufficient...

3.1. Using a dynamic/automatic address for em0
----------------------------------------------

If you are using DHCP (automatic address configuration, i.e. from a DSL
modem, or similar) it should be sufficient to run:

	# dhclient em0

3.2. Using a static address for em0
-----------------------------------

If you are not using DHCP, and you have a `static' address, like the one
I use on the workstation I'm using to type this, you should be able to
use ifconfig like:

	# ifconfig inet a.b.c.d/count up

where `a.b.c.d' is the IP address you want to assign, and `count' a
number like `24' or `28'.  The correct settings depends on how your
network is configured, but an example would look like:

	# ifconfig em0 192.168.1.180/24 up

4. Check that em0 really got an address and is "UP"
---------------------------------------------------

Then you should see something like:

	em0: flags=8802<UP,BROADCAST, SIMPLEX, MULTICAST> mtu 1500
		options=b<RXSCUM, TXSCUM, VLAN_MTU>
		ether :0d:56:f0:f1:ba
		inet 192.168.1.180 netmask 0xffffff00 broadcast 192.168.1.255
		media:Ethernet autoselect (100baseTX <full-duplex>)
		status: active

5. Add the default router/gateway
---------------------------------

If you see the "UP" flag in the first line, and you get the `inet' line
options correctly (address and netmask), the final step should be to
configure the `default router', i.e.:

	# route add default 192.168.1.1

6. Saving it all in `/etc/rc.conf' for the next boot
----------------------------------------------------

If you get all the steps right, and you _do_ get connectivity going,
then you should be able to manually edit the file `/etc/rc.conf' and set
configure everything by using something similar to:

	network_interfaces='lo0 em0'
	ifconfig_lo0='inet 127.0.0.1/32'
	ifconfig_em0='inet 192.168.1.180/24'
	defaultrouter='192.168.1.1'

The syntax is really simple, but if you need an explanation of what it
all means, please feel free to ask :)

- Giorgos