Re: [ECOS] DHCP w/ Win2K server?

[Grant Edwards <grante at visi dot com>]

On Fri, Nov 30, 2001 at 01:11:01PM +0000, Hugo Tyson wrote:

> > I believe it will be good to add that tag to all *FOUR* places DHCP sends a
> > packet, DHCPSTATE_REQUESTING, RENEWING, REBINDING and the initial broadcast
> > one in INIT.  'Course I'll test it, but only with LINUX dhcpd.  
> 
> Interesting.  The LINUX dhcpd normally returns all these DHCP options:
>         DHCP message: 5 ACK
>         DHCP server id: 10.16.19.66
>         DHCP time 51: 60
>         DHCP time 58: 30
>         DHCP time 59: 52
>         subnet mask: 255.255.255.0
>             gateway: 10.16.19.66
>       domain server: 10.16.19.66
>         domain name: hmt10.cambridge.redhat.com
>        IP broadcast: 10.16.19.255
> 
> (Yes, this lease is very very short, it's my testbench obviously)
> If I add:
> 
>     set_fixed_tag( xmit, TAG_DHCP_PARM_REQ_LIST, TAG_GATEWAY, 1 );
> 
> then all I get back are these:
>         DHCP message: 5 ACK
>         DHCP server id: 10.16.19.66
>         DHCP time 51: 60
>             gateway: 10.16.19.66
> 
> (whether I add it in INIT case or not)
> 
> It seems obvious that what's happening is this: if the LINUX dhcpd sees no
> specific option requests, it uses a sensible and generous list; if it sees
> any specific request, it sends that option *only*.

Rats.  Mine does the same thing (even the 60 second lease
time).  Why didn't I notice that?

> So for backward compatibility, I shall add specific requests
> for *all* those options that I am used to seeing - the absence
> of the "half time" and "nearly done" times is particularly
> distressing.

As of a few months ago, those two times get defaulted to
reasonable values if they're not present (IIRC, the default
value calculation will match the default values used by the
Linux server: 1/2 and 3/4 of the lease time), but requesting
them is probably the right thing to do.

The lack of a netmask, OTOH, is the show stopper for me. :(

Fixing it's easy enough, but it's another half-day's worth of
electronic paper-shuffling to get the fix out.

-- 
Grant Edwards
grante@visi.com