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

[Mick]

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?


> 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"



>   The 2nd interface is no longer being set up.  As amatter of fact, it
> appears to be totally unavailable.  E.g....
>
> [d531][root][~] /etc/init.d/net.eth0 stop
>  * Unmounting network filesystems ...                                     [
> ok ] * Bringing down interface eth0
> [d531][root][~] ifconfig eth0:0 192.168.123.251/29 broadcast
> 192.168.123.255 SIOCSIFNETMASK: Cannot assign requested address
> [d531][root][~] ifconfig eth0 192.168.123.251/29 broadcast 192.168.123.255
> [d531][root][~]
>
>   So my system doesn't support even the concept of an alias for eth0.
> Looking at the ifconfig manpage...

Unless you have set up:

modules="!iproute2"

netifrc will not use ifconfig.

> interface
>        The  name  of the interface.  This is usually a driver name fol-
>        lowed by a unit number, for example eth0 for the first  Ethernet
>        interface.  If  your  kernel  supports alias interfaces, you can
>        specify them with eth0:0 for the first alias of  eth0.  You  can
>        use  them  to assign a second address. To delete an alias inter-
>        face use ifconfig eth0:0 down.  Note: for every scope (i.e. same
>        net  with  address/netmask combination) all aliases are deleted,
>        if you delete the first (primary).
>
>   I see "If  your  kernel  supports alias interfaces".  During the
> upgrade, I built the kernel from square 1.  I already ran into problems
> with not enabling FUSE in the new kernel, which killed MTP until I
> enabled it.  I wouldn't be surprised if I've disabled some kernel
> parameter which is required to enable interface aliases.  I didn't see
> anything obvious in "make menuconfig".  A Google search turned up a
> gazillion examples of "how to create an alias using ifconfig".  That's
> not what I want.  I want the kernel setting that allows creating alias
> interfaces.

The kernel option you want is:

CONFIG_IP_MULTIPLE_TABLES=y


Also, if you want to set up the HDHomerun to do the right thing, i.e. NOT use 
local-link addresses, then according to Google you could try:

“A static IP address can be configured using the following command (the quotes 
are required as shown):
Format:  hdhomerun_config <old ip> set /sys/ipaddr "<new ip> <subnet> 
<gateway>"
Example: hdhomerun_config 169.254.34.98 set /sys/ipaddr "10.10.20.43 
255.255.255.0 10.10.20.1"

The TECH3 can be configured for DHCP operation (default) using the following 
command:
Format:  hdhomerun_config <old ip> set /sys/ipaddr dhcp
Example: hdhomerun_config 169.254.34.98 set /sys/ipaddr dhcp”


I think different variables can be saved in its /sys/boot, including a static 
IP address, so that they persist over reboots.

HTH
-- 
Regards,
Mick