Re: [Etherboot-developers] http/dns

[Markus G. <ma...@gu...>]

Ken Yap wrote:
> But they have to go through one menu to choose the NIC so why not do it
> all at once?

Do they? Can't we build a floppy image that includes all of our drivers? 
I thought this was supported with 5.2, but I haven't tested myself.

> I think gatewaying works for TFTP, which uses the first gateway
> specified in option-whatever as per RFC. There's no option to select a
> second or third gateway because there's no routing table. The other
> protocols should be written to do the same. This is of course providing
> the address handed out by DHCP is allowed by firewalls to connect to the
> Internet directly.

I believe, this should already work. The ip transmit code checks whether 
the packet should be sent to a host on the local network, and in that 
case sends it directly to that machine; if the the IP address does not 
match the local network address, all packets are sent to the default 
gateway. So, in a sense we do have a routing table -- it's just hardcoded.

> But note that many sites use a HTTP proxy so you'd have to get the HTTP
> code to understand proxies as well. The URL should also be kept short
> since it has to fit in 128 bytes, or was it 64?

It doesn't necessarily have to be this short. Things just get a little 
less efficient, because the request will be split across multiple TCP 
packets. In reality, this is not much of a problem.

> Well I have no objections if you write a resolver client that can be
> ifdefed. You'd have to query the DNS servers in option-whatever.

Having a resolver client would certainly be useful, if it could be made 
to fit in a small footprint.

> All this Etherboot development to support Debian loading? Now I know why
> dselect was so clunky. :-) Surely it's simpler to ask the user to run a
> HTTP proxy (probably about 50 lines of Perl) on an internal machine.

A lot of organizations have a pretty strict policy against running any 
kind of unauthorized server. That's the whole reason why I thought 
implementing HTTP could be useful. Fortunately, most of these places 
already have a DHCP server in place. So, they are almost set for Etherboot.

The only part that would missing is the URL that the DHCP server should 
sent. Users that find themselves in this position, can either try to 
persuade their IT department to advertise the right filename, or they'll 
have to resort to hardcoding the name into the image. I don't really 
like the latter, but realize that it is sometimes quite useful.



Markus