Re: How can I get the Linux Synthetic Target to use DHCP?

[Michael Bergandi <mbergandi at gmail dot com>]

Sergei,

> If you use an original 'ethernet.tdf' config file
>
> That is
>
> % egrep -v '(#|^\s*$)' $ECOS_REPOSITORY/devs/eth/synth/ecosynth/current/host/ethernet.tdf
>
> synth_device ethernet {
> ? ?eth0 ethertap tap3 00:FE:42:63:84:A5
> ? ?max_buffer 32
> }
>
> Let's notice that *ethertap* tap3 interface is used there.

Yes, I get the tap3 created.

tap3      Link encap:Ethernet  HWaddr b2:13:57:48:9e:f3
          inet6 addr: fe80::b013:57ff:fe48:9ef3/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:25 errors:0 dropped:0 overruns:0 frame:0
          TX packets:44 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:7650 (7.6 KB)  TX bytes:10945 (10.9 KB)

> Have you configured 'tap3' interface?

$ ifconfig tap3 up
$ ifconfig tap3

tap3      Link encap:Ethernet  HWaddr f6:9d:ca:9d:df:8c
          inet6 addr: fe80::f49d:caff:fe9d:df8c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:14 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:4788 (4.7 KB)  TX bytes:308 (308.0 B)

> Have you configured DHCP server on the interface? If you done it, Can you get IP address from DHCP pool on  the interface:

This is the problem. I am on a network which is running a dhcp server.
I don't have a specific dhcp server running on the host to handle only
that interface. Is that required?

Do I need to bridge the tap3 interface with an eth0/eth1 to get an
address from the dhcp server on the network?

> % sudo dhclient3 tap3

This just does what the hello-net app is already doing. No surprise,
it never gets an address either.

> There should be no surprise for you that if you want to use DHCP for
> synthetic target you have to configure and networking too.

Yeah, I expected to have to configure the networking some how.
Unfortunately, this is not in any of the documentation. I would expect
that there would at least be some mention of using dhcp with a
networked synthetic target app. Maybe even generalized steps for
getting your host configured to get it working.


> Well, I can guide how to get it working on Ubuntu, but I doubt that this
> list is the appropriate place for this.

That would be great.

I do think that this and probably the user list is the appropriate
place to address usage issue resulting from deficiencies in
documentation. Perhaps I can contribute some documentation once we get
this worked out.


-- 
Mike