dhcp on a direct connection

bigearsbilly · 11-23-2023, 05:26 AM

I am messing about with single board computers.
Now these generally start with DHCP.
I have got the DHCP running on my host to a network switch easy enough,
so I cam mess about and just plug any old SBC in and get a connection.

I am trying to work out if there is an easy way to
plug in directly to the host machine and have the DHCP work without
the switch, which saves on a power supply to plug in.
(and bridge to the internet would be nice)

bigearsbilly · 11-23-2023, 05:36 AM

Actually, I have just realised it's a silly question.

I take the cable out of the switch and plug it directly into the host and hey presto!

michaelk · 11-23-2023, 05:37 AM

An ethernet crossover cable should work regardless of type of adapter. Any computer within the last 10 years or so probably has mdi-x capability which automatically detects the connection so a crossover isn't necessary. Try a direct connection and if you see a link on the desktop it should work.

I missed your 2nd post...

bigearsbilly · 11-23-2023, 05:59 AM

Thanks anyway.
No I didn't need the crossover cable.

Now I need to work out how to get the SBC to the net via the host.

michaelk · 11-23-2023, 06:47 AM

Nat routing should be easy to setup. Make sure the dhcp server sends gateway and DNS addresses.

bigearsbilly · 11-23-2023, 09:23 AM

it's easy if you know how.
Not a clue, what tools do i use, is it a bridge, a tap/tun, iptables, a route or a flux capacitor?

michaelk · 11-23-2023, 01:39 PM

iptables or nftables depending on what is installed. Should be able to find masquerade rules by searching. Enable ip_forward for ipv4 in the kernel.

bigearsbilly · 11-24-2023, 03:36 AM

thanks michael, that points me in the right direction