# Network aliases and dhcp

## mole

Hi all,

I'm looking to replace my router/ssh/asterisk etc server setup with a small netbook to save a desktop PC running 24/7, I'd like to have a low-power setup using my Acer Aspire One which isn't doing much these days.

This netbook has only one network card and no PCMCIA slots.

Cable modem does not have USB networking facility

When I set up an alias eth0:1 for the local network, starting it with "ifconfig eth0:1 192.168.2.1 up" dhcp refuses to start as it doesn't "see" eth0:1 and thinks no interfaces are configured.

If I switch the network addresses around, and assign 192.168.2.1 to eth0, DHCPD starts fine, but the cable modem gives the wrong IP address to eth0:1 (although it is similar to the external IP address... eg 80.200.23.1 when the external IP address might be 86.23.432.12. When the modem's offline it gives out 192.168.100.xxx addresses)

I've tried starting eth0 with DHCP then swapping the assigned IP address over, so eth0 has 192.168.2.1 and eth0:1 has the modem external address, but the cable modem then blocks all traffic.

So I think the only option is to force DHCPD to start without the checks. Using the -f option doesn't work (not surprisingly as it only forces dhcpd to run as a foreground process, but worth a go   :Smile:  )

I can set up the internal PC's statically, but need DHCPD running to connect the phones using wireless.

Starting dhcpd directly - rather than /etc/init.d/dhcpd start makes no difference, so I can't see tweaking the init script working.

If I assign IP addresses DHCPD likes, then switch them over between the interfaces, DHCPD keeps running. It does seem to work, and could be set up with scripts but is very messy.

Is there any way of bypassing the DHCPD startup checks? Is it necessary to dig into the source code, disable and recompile?

----------

## mole

Only other thought is a USB -> Ethernet dongle...  but only one kernel option (for Net2280/SiS315) so not sure if the cheap ones would work with Linux.

----------

## mole

It's messy to restart and re-allocate IP addresses but it works, so am sticking with that.

Just in case anyone's interested in the performance of a 100mb/s network card with traffic going in and out rather than the theoretically much better 2 NIC setup, I've just checked the internet performance and the 30 Mbit/s connection is running at full speed (that's from a PC on the internal network, not the netbook router) so pleasantly surprised.

Now to see if I can get the ath5k wireless chip running as a beacon so I can turn off the ADSL modem I'm using....  looks like an ath9k chip would be easier but hopefully I can set this older chip up with madwifi.

----------

