[gentoo-user] Re: [SOLVED] What happened to my 2nd eth0?

[Walter Dnes]

On Sun, Feb 22, 2015 at 09:01:47AM +0000, Mick wrote
> On Sunday 22 Feb 2015 04:52:34 Walter Dnes wrote:
> >   My DSL router modem is at 192.168.123.254.  I have an HDHomerun
> > network TV tuner that insists on coming up somewhere in the 169.254.X.Y
> > block.  Up until upgrading from 32 to 64 bits, I was able to see a 2nd
> > eth0 (i.e. eth0:1) using the following /etc/conf.d/net setup...
> >
> > config_eth0="
> > 192.168.123.251/29 broadcast 192.168.123.255
> > 169.254.1.1/16 broadcast 169.254.255.255"
>
> Is there a reason you need to define a broadcast if you are using CIDR
> notation?

  I've always done it that way.  At one time I had a router that could
be made to send logs to a specified IP address.  By setting their
broadcast addresses to 192.168.123.255, and having the router log to
that address, I could make both of my machines pick up the remote logs
from the router.

> > routes_eth0="
> > default via 192.168.123.254 metric 20
> > 192.168.123.248/29 via 192.168.123.254 metric 0
>
> Isn't the above redundant if you have defined an identical default route?
>
> > 169.254.0.0/16 via 169.254.1.1 metric 0"

  Another item that stopped working a while ago...

  I have a dialup connection for emergency backup use.  Before the
format of the /etc/conf.d/net file changed, I could simultaneously...

* have eth0 as default route with "expensive metric" 20
* have ppp0 take over when dialup is active, with a "cheaper metric"
* still be able to have my 2 machines talk to each other over eth0, even
  while the dialup connection ppp0 is active
* have eth0 take over again as default route when ppp0 drops

> Unless you have set up:
>
> modules="!iproute2"
>
> netifrc will not use ifconfig.

  I've noticed iproute2 showing up recently in emerge.  ***YES IT
WORKS***.  Thank you very much.  I am now getting OTA TV to my desktop
again.  Slight modification.  Using that search string in Google, I
found http://www.michaeldolan.com/Tutorials/Downloads/conf.d/net

  My revised /etc/conf.d/net script is

modules=( "!iproute2" )
config_eth0="
192.168.123.251/29 broadcast 192.168.123.255
169.254.1.1/16 broadcast 169.254.255.255"
routes_eth0="
default via 192.168.123.254 metric 20
192.168.123.248/29 via 192.168.123.254 metric 0
169.254.0.0/16 via 169.254.1.1 metric 0"

edit... I finally found the documentation (see below).  I still have to
fix up the "metric" and "broadcast" parameters.  For now, I'm happy to
have the TV signal coming to my desktop.

...and "ifconfig" returns...

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.123.251  netmask 255.255.255.248  broadcast 192.168.123.255
        ether 00:1d:09:96:6c:1c  txqueuelen 1000  (Ethernet)
        RX packets 1049019  bytes 1501104544 (1.3 GiB)
        RX errors 0  dropped 5  overruns 0  frame 0
        TX packets 569447  bytes 45295143 (43.1 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 20  memory 0xfdfc0000-fdfe0000  

eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 169.254.1.1  netmask 255.255.0.0  broadcast 169.254.255.255
        ether 00:1d:09:96:6c:1c  txqueuelen 1000  (Ethernet)
        device interrupt 20  memory 0xfdfc0000-fdfe0000  

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 0  (Local Loopback)
        RX packets 8  bytes 480 (480.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 8  bytes 480 (480.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

  I would have appreciated a news item telling me that /etc/conf.d/net
was going to change default behaviour, before it happened and caused
breakage on my system.  Or did it happen, and I missed it?

> CONFIG_IP_MULTIPLE_TABLES=y

  I do not have that option available it in my current kernel, or in the
backup from before I switched from 32-bit to 64-bit mode.  Not that it
matters, now that I have things working.


  Given that iproute2 is now the default, I assume that ifconfig will be
dropped sometime down the road.  Documentation "could be better".  At
the top of /etc/conf.d/net I see...
# This blank configuration will automatically use DHCP for any net.*
# scripts in /etc/init.d.  To create a more complete configuration,
# please review /etc/conf.d/net.example and save your configuration
# in /etc/conf.d/net (this file :]!).

# Actually /usr/share/doc/openrc-<version>/net.example is where to look
# for example setup.

  Guess what... neither of those example files exist.  It's actually
/usr/share/doc/netifrc-<version>/net.example.bz2 (Where would I be
without Google?)  Also using Google, I found
http://www.policyrouting.org/iproute2.doc.html which is quite complex.
Looks like it's time to play around with the "ip" command and try to
duplicate my current setup.  Does anyone have a multi-route setup
similar to mine configured with iproute2?  The net.example file says

# If you need more than one address, you can use something like this
# NOTE: ifconfig creates an aliased device for each extra IPv4 address
#       (eth0:1, eth0:2, etc)
#       iproute2 does not do this as there is no need to
# WARNING: You cannot mix multiple addresses on a line with other parameters!
#config_eth0="192.168.0.2/24 192.168.0.3/24 192.168.0.4/24"
# However, that only works with CIDR addresses, so you can't use
# netmask.

  What exactly do they mean by...
"iproute2 does not do this as there is no need to"

-- 
Walter Dnes <waltdnes@××××××××.org>
I don't run "desktop environments"; I run useful applications